Description
Mistune from 3.2.1 before 3.3.0 contains a CSS injection vulnerability that allows attackers controlling markdown input to inject arbitrary style declarations via the unvalidated figwidth option of the figure directive. Attackers can append declarations like background:url() to the rendered figure style attribute, forcing victim browsers to send requests to attacker servers and leak attribute values.
Published: 2026-10-22
Score: 5.3 Medium
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories

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History

Fri, 23 Oct 2026 12:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-79
References
Metrics threat_severity

None

 threat_severity

Moderate

Fri, 23 Oct 2026 04:00:00 +0000

Type Values Removed Values Added
First Time appeared Lepture
Lepture mistune
Vendors & Products Lepture
Lepture mistune

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

Type Values Removed Values Added
Description Mistune from 3.2.1 before 3.3.0 contains a CSS injection vulnerability that allows attackers controlling markdown input to inject arbitrary style declarations via the unvalidated figwidth option of the figure directive. Attackers can append declarations like background:url() to the rendered figure style attribute, forcing victim browsers to send requests to attacker servers and leak attribute values.
Title Mistune 3.2.1 before 3.3.0 CSS Injection via Figure Directive figwidth Option
First Time appeared Mistune Project
Mistune Project mistune
Weaknesses CWE-94
CPEs cpe:2.3:a:mistune_project:mistune:*:*:*:*:*:*:*:*
Vendors & Products Mistune Project
Mistune Project mistune
References
Metrics cvssV3_1

{'score': 4.7, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N'}

cvssV4_0

{'score': 5.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N'}

Subscriptions

Lepture Mistune
Mistune Project Mistune
cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-10-22T19:13:27.678Z

Reserved: 2026-10-22T11:20:02.626Z

Link: CVE-2026-115351

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2026-10-22T19:17:40.920

Modified: 2026-10-22T19:17:41.033

Link: CVE-2026-115351

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-10-22T19:13:27Z

Links: CVE-2026-115351 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-10-23T04:30:04Z

Weaknesses
  • CWE-79

    Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

  • CWE-94

    Improper Control of Generation of Code ('Code Injection')