CVE-2026-20221 - Vulnerability Details

- Multiple Cisco Products Snort 3 Generic Routing Encapsulation Denial of Service Vulnerabilities

Description

Multiple Cisco products are affected by a vulnerability in the generic routing encapsulation (GRE) tunnel decapsulation feature of the Snort 3 Detection Engine that could allow an unauthenticated, remote attacker to cause an unexpected restart of the Snort 3 Detection Engine.

This vulnerability is due to improper handling of nested GRE traffic. An attacker could exploit this vulnerability by sending a crafted GRE payload through an affected device. A successful exploit could allow the attacker to trigger an unexpected reload of the Snort 3 Detection Engine, resulting in either a bypass or denial of service (DoS) condition, depending on device configuration. For more information, see the section of this advisory. The Snort 3 Detection Engine will restart automatically. No manual intervention is required.

Published: 2026-10-21

Score: 5.8 Medium

EPSS: < 1% Very Low

KEV: No

Impact:

Action:

Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Cisco

Cisco Cyber Vision

unknown

Version	Status	Constraints
`3.0.0`	affected	—
`3.0.2`	affected	—
`3.0.3`	affected	—
`3.0.1`	affected	—
`3.1.0`	affected	—
`3.0.4`	affected	—
`3.1.1`	affected	—
`3.1.2`	affected	—
`3.2.0`	affected	—
`3.0.5`	affected	—
`3.2.1`	affected	—
`3.0.6`	affected	—
`3.2.2`	affected	—
`3.2.3`	affected	—
`3.2.4`	affected	—
`4.0.0`	affected	—
`4.0.1`	affected	—
`4.0.2`	affected	—
`4.0.3`	affected	—
`4.1.0`	affected	—
`4.1.1`	affected	—
`4.1.2`	affected	—
`4.1.3`	affected	—
`4.1.4`	affected	—
`4.2.0`	affected	—
`4.2.1`	affected	—
`4.1.5`	affected	—
`4.2.2`	affected	—
`4.2.X`	affected	—
`4.2.3`	affected	—
`4.2.4`	affected	—
`4.2.6`	affected	—
`4.1.6`	affected	—
`4.3.0`	affected	—
`4.3.1`	affected	—
`4.3.2`	affected	—
`4.3.3`	affected	—
`4.4.0`	affected	—
`4.4.1`	affected	—
`4.4.2`	affected	—
`4.4.3`	affected	—
`4.1.7`	affected	—
`5.0.0`	affected	—
`5.0.1`	affected	—
`5.0.2`	affected	—
`5.1.0`	affected	—
`5.1.1`	affected	—
`5.1.2`	affected	—
`5.1.3`	affected	—
`5.2.0`	affected	—
`5.2.1`	affected	—
`5.3.0`	affected	—
`5.3.1`	affected	—
`5.3.2`	affected	—
`5.3.3`	affected	—
`5.5.1`	affected	—
`5.6.1`	affected	—
`5.6.0`	affected	—
`5.4.0`	affected	—
`5.4.1`	affected	—
`5.4.2`	affected	—

Cisco

Cisco Open Source Snort3

unknown

Version	Status	Constraints
`3.12.2.0`	affected	—
`3.1.2.0`	affected	—
`3.1.3.0`	affected	—
`3.1.4.0`	affected	—
`3.1.5.0`	affected	—
`3.1.6.0`	affected	—
`3.1.7.0`	affected	—
`3.1.8.0`	affected	—
`3.1.9.0`	affected	—
`3.1.10.0`	affected	—
`3.1.12.0`	affected	—
`3.1.13.0`	affected	—
`3.1.14.0`	affected	—
`3.1.15.0`	affected	—
`3.1.16.0`	affected	—
`3.1.17.0`	affected	—
`3.1.18.0`	affected	—
`3.1.19.0`	affected	—
`3.1.20.0`	affected	—
`3.1.21.0`	affected	—
`3.1.22.0`	affected	—
`3.1.23.0`	affected	—
`3.1.24.0`	affected	—
`3.1.25.0`	affected	—
`3.1.27.0`	affected	—
`3.1.28.0`	affected	—
`3.1.29.0`	affected	—
`3.1.30.0`	affected	—
`3.1.31.0`	affected	—
`3.1.32.0`	affected	—
`3.1.36.0`	affected	—
`3.1.38.0`	affected	—
`3.1.39.0`	affected	—
`3.1.40.0`	affected	—
`3.1.41.0`	affected	—
`3.1.42.0`	affected	—
`3.1.43.0`	affected	—
`3.1.45.0`	affected	—
`3.1.47.0`	affected	—
`3.1.48.0`	affected	—
`3.1.50.0`	affected	—
`3.1.51.0`	affected	—
`3.1.52.0`	affected	—
`3.1.53.0`	affected	—
`3.1.55.0`	affected	—
`3.1.56.0`	affected	—
`3.1.57.0`	affected	—
`3.1.58.0`	affected	—
`3.1.59.0`	affected	—
`3.1.60.0`	affected	—
`3.1.61.0`	affected	—
`3.1.62.0`	affected	—
`3.1.63.0`	affected	—
`3.1.64.0`	affected	—
`3.1.65.0`	affected	—
`3.1.66.0`	affected	—
`3.1.67.0`	affected	—
`3.1.69.0`	affected	—
`3.1.70.0`	affected	—
`3.1.71.0`	affected	—
`3.1.72.0`	affected	—
`3.1.73.0`	affected	—
`3.1.74.0`	affected	—
`3.1.75.0`	affected	—
`3.1.76.0`	affected	—
`3.1.77.0`	affected	—
`3.1.78.0`	affected	—
`3.1.81.0`	affected	—
`3.1.82.0`	affected	—
`3.1.83.0`	affected	—
`3.1.84.0`	affected	—
`3.2.1.0`	affected	—
`3.2.2.0`	affected	—
`3.3.0.0`	affected	—
`3.3.1.0`	affected	—
`3.3.2.0`	affected	—
`3.3.3.0`	affected	—
`3.3.4.0`	affected	—
`3.3.5.0`	affected	—
`3.3.7.0`	affected	—
`3.5.0.0`	affected	—
`3.5.1.0`	affected	—
`3.8.1.0`	affected	—
`3.6.0.0`	affected	—
`3.6.2.0`	affected	—
`3.9.3.0`	affected	—
`3.7.2.0`	affected	—
`3.7.0.0`	affected	—
`3.9.6.0`	affected	—
`3.10.0.0`	affected	—
`3.10.2.0`	affected	—
`3.7.4.0`	affected	—
`3.9.0.0`	affected	—
`3.5.2.0`	affected	—
`3.12.1.0`	affected	—
`3.6.1.0`	affected	—
`3.9.2.0`	affected	—
`3.6.3.0`	affected	—
`3.9.5.0`	affected	—
`3.7.1.0`	affected	—
`3.9.7.0`	affected	—
`3.7.3.0`	affected	—
`3.10.1.0`	affected	—
`3.9.1.0`	affected	—
`3.11.1.0`	affected	—

Cisco

Cisco Secure Firewall Threat Defense (FTD) Software

unknown

Version	Status	Constraints
`7.0.0`	affected	—
`7.0.0.1`	affected	—
`7.0.1`	affected	—
`7.0.1.1`	affected	—
`7.0.2`	affected	—
`7.2.0`	affected	—
`7.0.2.1`	affected	—
`7.0.3`	affected	—
`7.2.0.1`	affected	—
`7.0.4`	affected	—
`7.2.1`	affected	—
`7.0.5`	affected	—
`7.3.0`	affected	—
`7.2.2`	affected	—
`7.2.3`	affected	—
`7.3.1`	affected	—
`7.2.4`	affected	—
`7.0.6`	affected	—
`7.2.5`	affected	—
`7.2.4.1`	affected	—
`7.3.1.1`	affected	—
`7.4.0`	affected	—
`7.0.6.1`	affected	—
`7.2.5.1`	affected	—
`7.4.1`	affected	—
`7.2.6`	affected	—
`7.0.6.2`	affected	—
`7.4.1.1`	affected	—
`7.2.7`	affected	—
`7.2.5.2`	affected	—
`7.3.1.2`	affected	—
`7.2.8`	affected	—
`7.6.0`	affected	—
`7.4.2`	affected	—
`7.2.8.1`	affected	—
`7.0.6.3`	affected	—
`7.4.2.1`	affected	—
`7.2.9`	affected	—
`7.0.7`	affected	—
`7.7.0`	affected	—
`7.4.2.2`	affected	—
`7.2.10`	affected	—
`7.6.1`	affected	—
`7.4.2.3`	affected	—
`7.0.8`	affected	—
`7.6.2`	affected	—
`7.7.10`	affected	—
`7.7.11`	affected	—
`7.0.8.1`	affected	—
`7.6.2.1`	affected	—
`7.7.10.1`	affected	—
`7.4.2.4`	affected	—
`7.2.10.2`	affected	—
`7.4.3`	affected	—
`7.6.4`	affected	—
`10.0.0`	affected	—
`7.4.4`	affected	—
`7.0.9`	affected	—
`7.2.11`	affected	—
`7.4.7`	affected	—

Cisco

Cisco Umbrella Insights Virtual Appliance

unknown

Version	Status	Constraints
`2.6.0`	affected	—
`2.5.6`	affected	—
`2.5`	affected	—
`2.4.12`	affected	—
`2.7`	affected	—
`2.6.2`	affected	—
`2.5.5`	affected	—
`2.5.4`	affected	—
`2.8`	affected	—
`2.6.1`	affected	—
`2.5.7`	affected	—
`1.5.4`	affected	—
`1.5.5`	affected	—
`1.5.6`	affected	—
`2.0.0`	affected	—
`2.0.2`	affected	—
`2.0.3`	affected	—
`2.1.0`	affected	—
`2.1.2`	affected	—
`2.1.4`	affected	—
`2.1.5`	affected	—
`2.2`	affected	—
`2.2.1`	affected	—
`2.3`	affected	—
`2.3.1`	affected	—
`2.4`	affected	—
`2.4.4`	affected	—
`2.4.6`	affected	—
`2.8.9`	affected	—
`3.0`	affected	—
`3.1`	affected	—
`3.2`	affected	—
`2.8.1`	affected	—
`2.8.2`	affected	—
`2.8.3`	affected	—
`2.8.4`	affected	—
`2.8.5`	affected	—
`3.0.1`	affected	—
`3.0.2`	affected	—
`3.0.4`	affected	—
`3.0.5`	affected	—
`3.1.1`	affected	—
`3.1.2`	affected	—
`3.1.3`	affected	—
`3.1.4`	affected	—
`3.2.1`	affected	—
`3.2.2`	affected	—
`3.2.3`	affected	—
`3.3`	affected	—
`3.3.1`	affected	—
`3.3.2`	affected	—
`3.3.3`	affected	—
`3.3.4`	affected	—
`3.4`	affected	—
`3.4.1`	affected	—
`3.4.2`	affected	—
`3.4.3`	affected	—
`3.4.4`	affected	—
`3.4.5`	affected	—
`3.4.6`	affected	—
`3.5`	affected	—
`2.7.1`	affected	—
`2.7.2`	affected	—
`2.7.6`	affected	—
`2.7.9`	affected	—
`2.7.10`	affected	—
`3.5.1`	affected	—
`3.5.2`	affected	—
`3.6.1`	affected	—
`3.6.2`	affected	—
`3.7`	affected	—
`3.7.1`	affected	—
`3.8.3`	affected	—

Cisco

Cisco UTD SNORT IPS Engine Software

unknown

Version	Status	Constraints
`3.17.1S`	affected	—
`16.12.3`	affected	—
`Fuji-16.9.5`	affected	—
`16.12.4`	affected	—
`17.3.1a`	affected	—
`16.6.6`	affected	—
`16.12.2`	affected	—
`Fuji-16.9.6`	affected	—
`3.17.0S`	affected	—
`Fuji-16.9.3`	affected	—
`Denali-16.3.7`	affected	—
`Fuji-16.9.2`	affected	—
`Fuji-16.9.4`	affected	—
`Everest-16.6.4`	affected	—
`Everest-16.6.3`	affected	—
`16.6.5`	affected	—
`Denali-16.3.5`	affected	—
`17.2.1r`	affected	—
`17.1.1`	affected	—
`Everest-16.6.2`	affected	—
`16.6.7a`	affected	—
`Denali-16.3.4`	affected	—
`16.6.1`	affected	—
`Denali-16.3.9`	affected	—
`Denali-16.3.3`	affected	—
`16.12.1a`	affected	—
`17.3.2`	affected	—
`17.4.1a`	affected	—
`16.12.5`	affected	—
`17.5.1`	affected	—
`Fuji-16.9.7`	affected	—
`16.6.9`	affected	—
`17.3.3`	affected	—
`17.5.1a`	affected	—
`17.3.4`	affected	—
`17.3.4a`	affected	—
`17.4.2`	affected	—
`17.4.1b`	affected	—
`17.6.1a`	affected	—
`16.6.10`	affected	—
`17.7.1a`	affected	—
`16.12.6`	affected	—
`Fuji-16.9.8`	affected	—
`17.6.2`	affected	—
`17.8.1a`	affected	—
`16.12.7`	affected	—
`17.3.5`	affected	—
`17.6.3`	affected	—
`17.6.3a`	affected	—
`17.7.2`	affected	—
`17.9.1a`	affected	—
`17.6.4`	affected	—
`17.10.1a`	affected	—
`17.3.6`	affected	—
`16.12.8`	affected	—
`17.3.7`	affected	—
`17.9.2a`	affected	—
`17.6.5`	affected	—
`17.11.1a`	affected	—
`17.9.3a`	affected	—
`17.12.1a`	affected	—
`17.9.4`	affected	—
`17.6.6`	affected	—
`17.3.8`	affected	—
`17.3.8a`	affected	—
`17.6.6a`	affected	—
`17.9.4a`	affected	—
`17.12.2`	affected	—
`17.13.1a`	affected	—
`17.9.5a`	affected	—
`17.12.3`	affected	—
`17.6.7`	affected	—
`17.14.1a`	affected	—
`17.12.4`	affected	—
`17.12.3a`	affected	—
`17.15.1a`	affected	—
`17.6.8`	affected	—
`17.9.6`	affected	—
`17.6.8a`	affected	—
`17.16.1a`	affected	—
`17.9.5e`	affected	—
`17.12.4a`	affected	—
`17.15.2c`	affected	—
`17.9.5f`	affected	—
`17.12.4b`	affected	—
`17.15.2a`	affected	—
`17.12.5`	affected	—
`17.17.1`	affected	—
`17.12.5a`	affected	—
`17.9.7a`	affected	—
`17.15.3a`	affected	—
`17.15.3`	affected	—
`17.12.5b`	affected	—
`17.12.5c`	affected	—
`17.15.4`	affected	—
`17.9.7b`	affected	—
`17.18.1`	affected	—
`17.18.1a`	affected	—
`17.12.6`	affected	—
`17.9.8`	affected	—
`17.15.4c`	affected	—
`17.12.5d`	affected	—
`17.18.2`	affected	—
`26.1.1`	affected	—
`17.15.5`	affected	—
`17.15.5a`	affected	—
`17.12.7`	affected	—
`17.12.7a`	affected	—
`17.12.7b`	affected	—
`17.9.9`	affected	—
`17.18.3a`	affected	—
`17.12.8`	affected	—
`17.15.6`	affected	—
`17.18.4`	affected	—
`26.1.2`	affected	—
`17.9.10`	affected	—

No data.

Vendor Product Confidence Versions

Cisco

Cisco Open Source Snort3

100%

Version	Status	Scheme	Platform
`3.12.2.0`	affected	generic	—
`3.1.2.0`	affected	generic	—
`3.1.3.0`	affected	generic	—
`3.1.4.0`	affected	generic	—
`3.1.5.0`	affected	generic	—
`3.1.6.0`	affected	generic	—
`3.1.7.0`	affected	generic	—
`3.1.8.0`	affected	generic	—
`3.1.9.0`	affected	generic	—
`3.1.10.0`	affected	generic	—
`3.1.12.0`	affected	generic	—
`3.1.13.0`	affected	generic	—
`3.1.14.0`	affected	generic	—
`3.1.15.0`	affected	generic	—
`3.1.16.0`	affected	generic	—
`3.1.17.0`	affected	generic	—
`3.1.18.0`	affected	generic	—
`3.1.19.0`	affected	generic	—
`3.1.20.0`	affected	generic	—
`3.1.21.0`	affected	generic	—
`3.1.22.0`	affected	generic	—
`3.1.23.0`	affected	generic	—
`3.1.24.0`	affected	generic	—
`3.1.25.0`	affected	generic	—
`3.1.27.0`	affected	generic	—
`3.1.28.0`	affected	generic	—
`3.1.29.0`	affected	generic	—
`3.1.30.0`	affected	generic	—
`3.1.31.0`	affected	generic	—
`3.1.32.0`	affected	generic	—
`3.1.36.0`	affected	generic	—
`3.1.38.0`	affected	generic	—
`3.1.39.0`	affected	generic	—
`3.1.40.0`	affected	generic	—
`3.1.41.0`	affected	generic	—
`3.1.42.0`	affected	generic	—
`3.1.43.0`	affected	generic	—
`3.1.45.0`	affected	generic	—
`3.1.47.0`	affected	generic	—
`3.1.48.0`	affected	generic	—
`3.1.50.0`	affected	generic	—
`3.1.51.0`	affected	generic	—
`3.1.52.0`	affected	generic	—
`3.1.53.0`	affected	generic	—
`3.1.55.0`	affected	generic	—
`3.1.56.0`	affected	generic	—
`3.1.57.0`	affected	generic	—
`3.1.58.0`	affected	generic	—
`3.1.59.0`	affected	generic	—
`3.1.60.0`	affected	generic	—
`3.1.61.0`	affected	generic	—
`3.1.62.0`	affected	generic	—
`3.1.63.0`	affected	generic	—
`3.1.64.0`	affected	generic	—
`3.1.65.0`	affected	generic	—
`3.1.66.0`	affected	generic	—
`3.1.67.0`	affected	generic	—
`3.1.69.0`	affected	generic	—
`3.1.70.0`	affected	generic	—
`3.1.71.0`	affected	generic	—
`3.1.72.0`	affected	generic	—
`3.1.73.0`	affected	generic	—
`3.1.74.0`	affected	generic	—
`3.1.75.0`	affected	generic	—
`3.1.76.0`	affected	generic	—
`3.1.77.0`	affected	generic	—
`3.1.78.0`	affected	generic	—
`3.1.81.0`	affected	generic	—
`3.1.82.0`	affected	generic	—
`3.1.83.0`	affected	generic	—
`3.1.84.0`	affected	generic	—
`3.2.1.0`	affected	generic	—
`3.2.2.0`	affected	generic	—
`3.3.0.0`	affected	generic	—
`3.3.1.0`	affected	generic	—
`3.3.2.0`	affected	generic	—
`3.3.3.0`	affected	generic	—
`3.3.4.0`	affected	generic	—
`3.3.5.0`	affected	generic	—
`3.3.7.0`	affected	generic	—
`3.5.0.0`	affected	generic	—
`3.5.1.0`	affected	generic	—
`3.8.1.0`	affected	generic	—
`3.6.0.0`	affected	generic	—
`3.6.2.0`	affected	generic	—
`3.9.3.0`	affected	generic	—
`3.7.2.0`	affected	generic	—
`3.7.0.0`	affected	generic	—
`3.9.6.0`	affected	generic	—
`3.10.0.0`	affected	generic	—
`3.10.2.0`	affected	generic	—
`3.7.4.0`	affected	generic	—
`3.9.0.0`	affected	generic	—
`3.5.2.0`	affected	generic	—
`3.12.1.0`	affected	generic	—
`3.6.1.0`	affected	generic	—
`3.9.2.0`	affected	generic	—
`3.6.3.0`	affected	generic	—
`3.9.5.0`	affected	generic	—
`3.7.1.0`	affected	generic	—
`3.9.7.0`	affected	generic	—
`3.7.3.0`	affected	generic	—
`3.10.1.0`	affected	generic	—
`3.9.1.0`	affected	generic	—
`3.11.1.0`	affected	generic	—

Cisco

Cisco Secure Firewall Threat Defense (ftd) Software

100%

Version	Status	Scheme	Platform
`7.0.0`	affected	semver	—
`7.0.0.1`	affected	generic	—
`7.0.1`	affected	semver	—
`7.0.1.1`	affected	generic	—
`7.0.2`	affected	semver	—
`7.2.0`	affected	semver	—
`7.0.2.1`	affected	generic	—
`7.0.3`	affected	semver	—
`7.2.0.1`	affected	generic	—
`7.0.4`	affected	semver	—
`7.2.1`	affected	semver	—
`7.0.5`	affected	semver	—
`7.3.0`	affected	semver	—
`7.2.2`	affected	semver	—
`7.2.3`	affected	semver	—
`7.3.1`	affected	semver	—
`7.2.4`	affected	semver	—
`7.0.6`	affected	semver	—
`7.2.5`	affected	semver	—
`7.2.4.1`	affected	generic	—
`7.3.1.1`	affected	semver	—
`7.4.0`	affected	semver	—
`7.0.6.1`	affected	semver	—
`7.2.5.1`	affected	semver	—
`7.4.1`	affected	semver	—
`7.2.6`	affected	semver	—
`7.0.6.2`	affected	semver	—
`7.4.1.1`	affected	semver	—
`7.2.7`	affected	semver	—
`7.2.5.2`	affected	semver	—
`7.3.1.2`	affected	semver	—
`7.2.8`	affected	semver	—
`7.6.0`	affected	semver	—
`7.4.2`	affected	semver	—
`7.2.8.1`	affected	semver	—
`7.0.6.3`	affected	semver	—
`7.4.2.1`	affected	semver	—
`7.2.9`	affected	semver	—
`7.0.7`	affected	semver	—
`7.7.0`	affected	semver	—
`7.4.2.2`	affected	semver	—
`7.2.10`	affected	semver	—
`7.6.1`	affected	semver	—
`7.4.2.3`	affected	semver	—
`7.0.8`	affected	semver	—
`7.6.2`	affected	semver	—
`7.7.10`	affected	semver	—
`7.7.11`	affected	semver	—
`7.0.8.1`	affected	semver	—
`7.6.2.1`	affected	semver	—
`7.7.10.1`	affected	semver	—
`7.4.2.4`	affected	semver	—
`7.2.10.2`	affected	semver	—
`7.4.3`	affected	semver	—
`7.6.4`	affected	semver	—
`10.0.0`	affected	semver	—
`7.4.4`	affected	semver	—
`7.0.9`	affected	semver	—
`7.2.11`	affected	semver	—
`7.4.7`	affected	semver	—

Cisco

Cisco Utd Snort Ips Engine Software

100%

Version	Status	Scheme	Platform
`3.17.1S`	affected	generic	—
`16.12.3`	affected	generic	—
`Fuji-16.9.5`	affected	generic	—
`16.12.4`	affected	generic	—
`17.3.1a`	affected	generic	—
`16.6.6`	affected	generic	—
`16.12.2`	affected	generic	—
`Fuji-16.9.6`	affected	generic	—
`3.17.0S`	affected	generic	—
`Fuji-16.9.3`	affected	generic	—
`Denali-16.3.7`	affected	generic	—
`Fuji-16.9.2`	affected	generic	—
`Fuji-16.9.4`	affected	generic	—
`Everest-16.6.4`	affected	generic	—
`Everest-16.6.3`	affected	generic	—
`16.6.5`	affected	generic	—
`Denali-16.3.5`	affected	generic	—
`17.2.1r`	affected	generic	—
`17.1.1`	affected	generic	—
`Everest-16.6.2`	affected	generic	—
`16.6.7a`	affected	generic	—
`Denali-16.3.4`	affected	generic	—
`16.6.1`	affected	generic	—
`Denali-16.3.9`	affected	generic	—
`Denali-16.3.3`	affected	generic	—
`16.12.1a`	affected	generic	—
`17.3.2`	affected	generic	—
`17.4.1a`	affected	generic	—
`16.12.5`	affected	generic	—
`17.5.1`	affected	generic	—
`Fuji-16.9.7`	affected	generic	—
`16.6.9`	affected	generic	—
`17.3.3`	affected	generic	—
`17.5.1a`	affected	generic	—
`17.3.4`	affected	generic	—
`17.3.4a`	affected	generic	—
`17.4.2`	affected	generic	—
`17.4.1b`	affected	generic	—
`17.6.1a`	affected	generic	—
`16.6.10`	affected	generic	—
`17.7.1a`	affected	generic	—
`16.12.6`	affected	generic	—
`Fuji-16.9.8`	affected	generic	—
`17.6.2`	affected	generic	—
`17.8.1a`	affected	generic	—
`16.12.7`	affected	generic	—
`17.3.5`	affected	generic	—
`17.6.3`	affected	generic	—
`17.6.3a`	affected	generic	—
`17.7.2`	affected	generic	—
`17.9.1a`	affected	generic	—
`17.6.4`	affected	generic	—
`17.10.1a`	affected	generic	—
`17.3.6`	affected	generic	—
`16.12.8`	affected	generic	—
`17.3.7`	affected	generic	—
`17.9.2a`	affected	generic	—
`17.6.5`	affected	generic	—
`17.11.1a`	affected	generic	—
`17.9.3a`	affected	generic	—
`17.12.1a`	affected	generic	—
`17.9.4`	affected	generic	—
`17.6.6`	affected	generic	—
`17.3.8`	affected	generic	—
`17.3.8a`	affected	generic	—
`17.6.6a`	affected	generic	—
`17.9.4a`	affected	generic	—
`17.12.2`	affected	generic	—
`17.13.1a`	affected	generic	—
`17.9.5a`	affected	generic	—
`17.12.3`	affected	generic	—
`17.6.7`	affected	generic	—
`17.14.1a`	affected	generic	—
`17.12.4`	affected	generic	—
`17.12.3a`	affected	generic	—
`17.15.1a`	affected	generic	—
`17.6.8`	affected	generic	—
`17.9.6`	affected	generic	—
`17.6.8a`	affected	generic	—
`17.16.1a`	affected	generic	—
`17.9.5e`	affected	generic	—
`17.12.4a`	affected	generic	—
`17.15.2c`	affected	generic	—
`17.9.5f`	affected	generic	—
`17.12.4b`	affected	generic	—
`17.15.2a`	affected	generic	—
`17.12.5`	affected	generic	—
`17.17.1`	affected	generic	—
`17.12.5a`	affected	generic	—
`17.9.7a`	affected	generic	—
`17.15.3a`	affected	generic	—
`17.15.3`	affected	generic	—
`17.12.5b`	affected	generic	—
`17.12.5c`	affected	generic	—
`17.15.4`	affected	generic	—
`17.9.7b`	affected	generic	—
`17.18.1`	affected	generic	—
`17.18.1a`	affected	generic	—
`17.12.6`	affected	generic	—
`17.9.8`	affected	generic	—
`17.15.4c`	affected	generic	—
`17.12.5d`	affected	generic	—
`17.18.2`	affected	generic	—
`26.1.1`	affected	generic	—
`17.15.5`	affected	generic	—
`17.15.5a`	affected	generic	—
`17.12.7`	affected	generic	—
`17.12.7a`	affected	generic	—
`17.12.7b`	affected	generic	—
`17.9.9`	affected	generic	—
`17.18.3a`	affected	generic	—
`17.12.8`	affected	generic	—
`17.15.6`	affected	generic	—
`17.18.4`	affected	generic	—
`26.1.2`	affected	generic	—
`17.9.10`	affected	generic	—

Cisco

Cyber Vision

100%

Version	Status	Scheme	Platform
`3.0.0`	affected	semver	—
`3.0.2`	affected	semver	—
`3.0.3`	affected	semver	—
`3.0.1`	affected	semver	—
`3.1.0`	affected	semver	—
`3.0.4`	affected	semver	—
`3.1.1`	affected	semver	—
`3.1.2`	affected	semver	—
`3.2.0`	affected	semver	—
`3.0.5`	affected	semver	—
`3.2.1`	affected	semver	—
`3.0.6`	affected	semver	—
`3.2.2`	affected	semver	—
`3.2.3`	affected	semver	—
`3.2.4`	affected	semver	—
`4.0.0`	affected	semver	—
`4.0.1`	affected	semver	—
`4.0.2`	affected	semver	—
`4.0.3`	affected	semver	—
`4.1.0`	affected	semver	—
`4.1.1`	affected	semver	—
`4.1.2`	affected	semver	—
`4.1.3`	affected	semver	—
`4.1.4`	affected	semver	—
`4.2.0`	affected	semver	—
`4.2.1`	affected	semver	—
`4.1.5`	affected	semver	—
`4.2.2`	affected	semver	—
`4.2.X`	affected	generic	—
`4.2.3`	affected	semver	—
`4.2.4`	affected	semver	—
`4.2.6`	affected	semver	—
`4.1.6`	affected	semver	—
`4.3.0`	affected	semver	—
`4.3.1`	affected	semver	—
`4.3.2`	affected	semver	—
`4.3.3`	affected	semver	—
`4.4.0`	affected	semver	—
`4.4.1`	affected	semver	—
`4.4.2`	affected	semver	—
`4.4.3`	affected	semver	—
`4.1.7`	affected	semver	—
`5.0.0`	affected	semver	—
`5.0.1`	affected	semver	—
`5.0.2`	affected	semver	—
`5.1.0`	affected	semver	—
`5.1.1`	affected	semver	—
`5.1.2`	affected	semver	—
`5.1.3`	affected	semver	—
`5.2.0`	affected	semver	—
`5.2.1`	affected	semver	—
`5.3.0`	affected	semver	—
`5.3.1`	affected	semver	—
`5.3.2`	affected	semver	—
`5.3.3`	affected	semver	—
`5.5.1`	affected	semver	—
`5.6.1`	affected	semver	—
`5.6.0`	affected	semver	—
`5.4.0`	affected	semver	—
`5.4.1`	affected	semver	—
`5.4.2`	affected	semver	—

Cisco

Secure Firewall Threat Defense

100%

Version	Status	Scheme	Platform
`7.0.0`	affected	semver	—
`7.0.0.1`	affected	generic	—
`7.0.1`	affected	semver	—
`7.0.1.1`	affected	generic	—
`7.0.2`	affected	semver	—
`7.2.0`	affected	semver	—
`7.0.2.1`	affected	generic	—
`7.0.3`	affected	semver	—
`7.2.0.1`	affected	generic	—
`7.0.4`	affected	semver	—
`7.2.1`	affected	semver	—
`7.0.5`	affected	semver	—
`7.3.0`	affected	semver	—
`7.2.2`	affected	semver	—
`7.2.3`	affected	semver	—
`7.3.1`	affected	semver	—
`7.2.4`	affected	semver	—
`7.0.6`	affected	semver	—
`7.2.5`	affected	semver	—
`7.2.4.1`	affected	generic	—
`7.3.1.1`	affected	semver	—
`7.4.0`	affected	semver	—
`7.0.6.1`	affected	semver	—
`7.2.5.1`	affected	semver	—
`7.4.1`	affected	semver	—
`7.2.6`	affected	semver	—
`7.0.6.2`	affected	semver	—
`7.4.1.1`	affected	semver	—
`7.2.7`	affected	semver	—
`7.2.5.2`	affected	semver	—
`7.3.1.2`	affected	semver	—
`7.2.8`	affected	semver	—
`7.6.0`	affected	semver	—
`7.4.2`	affected	semver	—
`7.2.8.1`	affected	semver	—
`7.0.6.3`	affected	semver	—
`7.4.2.1`	affected	semver	—
`7.2.9`	affected	semver	—
`7.0.7`	affected	semver	—
`7.7.0`	affected	semver	—
`7.4.2.2`	affected	semver	—
`7.2.10`	affected	semver	—
`7.6.1`	affected	semver	—
`7.4.2.3`	affected	semver	—
`7.0.8`	affected	semver	—
`7.6.2`	affected	semver	—
`7.7.10`	affected	semver	—
`7.7.11`	affected	semver	—
`7.0.8.1`	affected	semver	—
`7.6.2.1`	affected	semver	—
`7.7.10.1`	affected	semver	—
`7.4.2.4`	affected	semver	—
`7.2.10.2`	affected	semver	—
`7.4.3`	affected	semver	—
`7.6.4`	affected	semver	—
`10.0.0`	affected	semver	—
`7.4.4`	affected	semver	—
`7.0.9`	affected	semver	—
`7.2.11`	affected	semver	—
`7.4.7`	affected	semver	—

Cisco

Umbrella Insights Virtual Appliance

100%

Version	Status	Scheme	Platform
`2.6.0`	affected	semver	—
`2.5.6`	affected	semver	—
`2.5`	affected	generic	—
`2.6`	affected	generic	—
`2.4.12`	affected	semver	—
`2.7`	affected	semver	—
`2.6.2`	affected	semver	—
`2.6.1`	affected	semver	—
`2.5.7`	affected	semver	—
`1.5.4`	affected	semver	—
`1.5.5`	affected	semver	—
`1.5.6`	affected	semver	—
`2.0.0`	affected	semver	—
`2.0.2`	affected	semver	—
`2.0.3`	affected	semver	—
`2.1.0`	affected	semver	—
`2.1.2`	affected	semver	—
`2.1.4`	affected	semver	—
`2.1.5`	affected	semver	—
`2.2`	affected	semver	—
`2.2.1`	affected	semver	—
`2.3`	affected	semver	—
`2.3.1`	affected	semver	—
`2.4`	affected	generic	—
`2.4.4`	affected	semver	—
`2.4.6`	affected	semver	—
`2.8`	affected	semver	—
`3.0`	affected	generic	—
`3.0.1`	affected	semver	—
`3.0.2`	affected	semver	—
`3.0.3`	affected	semver	—
`3.0.4`	affected	semver	—
`3.1.1`	affected	semver	—
`3.1.2`	affected	semver	—
`3.1.3`	affected	semver	—
`3.1.4`	affected	semver	—
`3.1.5`	affected	semver	—
`3.2.1`	affected	semver	—
`3.2.2`	affected	semver	—
`3.2.3`	affected	semver	—
`3.3`	affected	semver	—
`3.3.1`	affected	semver	—
`3.3.2`	affected	semver	—
`3.3.3`	affected	semver	—
`3.4`	affected	semver	—
`3.4.1`	affected	semver	—
`3.4.2`	affected	semver	—
`3.4.3`	affected	semver	—
`3.4.4`	affected	semver	—
`3.4.5`	affected	semver	—
`3.4.6`	affected	semver	—
`3.5`	affected	semver	—
`2.7.1`	affected	semver	—
`2.7.2`	affected	semver	—
`2.7.6`	affected	semver	—
`2.7.9`	affected	semver	—
`2.7.10`	affected	semver	—
`3.5.1`	affected	semver	—
`3.5.2`	affected	semver	—
`3.6.1`	affected	semver	—
`3.6.2`	affected	semver	—
`3.7`	affected	semver	—
`3.7.1`	affected	semver	—
`3.8.3`	affected	semver	—

Found an issue or want to improve our Enrichment? You can suggest it directly by opening an issue on our dedicated GitHub repository .

Remediation

No vendor fix or workaround currently provided.

Additional remediation guidance may be available on OpenCVE Cloud.

Tracking

Sign in to view the affected projects.

Advisories

No advisories yet.

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Changed

Confidentiality Impact None

Integrity Impact None

Availability Impact Low

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00454.

Exploitation none

Automatable yes

Technical Impact partial

References

Link	Providers
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort3-gre-JNpMHrTv

History

Fri, 23 Oct 2026 00:45:00 +0000

Type	Values Removed	Values Added
First Time appeared		Cisco Cisco cisco Open Source Snort3 Cisco cisco Secure Firewall Threat Defense (ftd) Software Cisco cisco Utd Snort Ips Engine Software Cisco cyber Vision Cisco secure Firewall Threat Defense Cisco umbrella Insights Virtual Appliance
Vendors & Products		Cisco Cisco cisco Open Source Snort3 Cisco cisco Secure Firewall Threat Defense (ftd) Software Cisco cisco Utd Snort Ips Engine Software Cisco cyber Vision Cisco secure Firewall Threat Defense Cisco umbrella Insights Virtual Appliance

Thu, 22 Oct 2026 14:30:00 +0000

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Wed, 21 Oct 2026 17:15:00 +0000

Type	Values Removed	Values Added
Description		Multiple Cisco products are affected by a vulnerability in the generic routing encapsulation (GRE) tunnel decapsulation feature of the Snort 3 Detection Engine that could allow an unauthenticated, remote attacker to cause an unexpected restart of the Snort 3 Detection Engine. This vulnerability is due to improper handling of nested GRE traffic. An attacker could exploit this vulnerability by sending a crafted GRE payload through an affected device. A successful exploit could allow the attacker to trigger an unexpected reload of the Snort 3 Detection Engine, resulting in either a bypass or denial of service (DoS) condition, depending on device configuration. For more information, see the section of this advisory. The Snort 3 Detection Engine will restart automatically. No manual intervention is required.
Title		Multiple Cisco Products Snort 3 Generic Routing Encapsulation Denial of Service Vulnerabilities
Weaknesses		CWE-476
References		https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort3-gre-JNpMHrTv
Metrics		cvssV3_1 `{'score': 5.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L'}`

Subscriptions

Cisco Cisco Open Source Snort3 Cisco Secure Firewall Threat Defense (ftd) Software Cisco Utd Snort Ips Engine Software Cyber Vision Secure Firewall Threat Defense Umbrella Insights Virtual Appliance

MITRE

Status: PUBLISHED

Assigner: cisco

Published: 2026-10-21T16:12:53.435Z

Updated: 2026-10-22T19:11:26.546Z

Reserved: 2025-10-08T11:59:15.398Z

Link: CVE-2026-20221

Vulnrichment

Updated: 2026-10-22T13:36:52.741Z

NVD

Status : Awaiting Analysis

Published: 2026-10-21T17:18:27.947

Modified: 2026-10-22T14:17:40.940

Link: CVE-2026-20221

Redhat

No data.

OpenCVE Enrichment

Updated: 2026-10-22T20:30:12Z

Weaknesses

CWE-476
NULL Pointer Dereference

Tracking

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Changed

Confidentiality Impact None

Integrity Impact None

Availability Impact Low

User Interaction None

Exploitation none

Automatable yes

Technical Impact partial

Subscriptions

JSON object

JSON object

JSON object

JSON object

JSON object