| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| Loop with Unreachable Exit Condition ('Infinite Loop') vulnerability in Erlang OTP ssh (ssh_sftpd module) allows an authenticated SFTP user to render an SFTP channel permanently unresponsive.
The handle_data/4 function in ssh_sftpd contains a catch-all clause that accepts channel data of any type. When channel data with a non-zero type code (SSH_MSG_CHANNEL_EXTENDED_DATA) arrives with an empty pending buffer and a payload at or below the SFTP packet size limit, the clause tail-calls itself with identical arguments, creating an infinite loop.
The SFTP protocol operates exclusively on normal channel data (type 0). Extended data (non-zero type) is meaningless for SFTP and is never sent by conforming clients. However, the SSH protocol permits any channel participant to send extended data on an open channel, so an authenticated SFTP client can trigger the loop by sending SSH_MSG_CHANNEL_EXTENDED_DATA with any data_type_code and any non-empty payload at or below the size limit.
The targeted ssh_sftpd process enters an infinite tail-recursive loop. It never processes another message, its message queue grows without bound, and it can only be stopped by killing the process. BEAM's reduction-based scheduler preemption continues to function, so other processes on the node are not starved, but each stuck channel process consumes its full CPU time share continuously and accumulates unbounded message queue memory. Opening many channels amplifies the CPU and memory impact.
Erlang/OTP SSH configurations using the default max_channels setting (infinity) allow an authenticated user to open unlimited channels per connection, amplifying the attack without requiring multiple TCP connections or authentications.
No file contents, credentials, or write access are obtainable through this issue. The impact is limited to denial of service on targeted SFTP channels, with secondary CPU degradation and memory growth.
This vulnerability is associated with program file lib/ssh/src/ssh_sftpd.erl and program routine ssh_sftpd:handle_data/4.
This issue affects OTP from OTP 17.0 before OTP 29.0.3, OTP 28.5.0.3 and OTP 27.3.4.14, corresponding to ssh from 3.0.1 before 6.0.2, 5.5.2.2 and 5.2.11.9. |
| HTML::Bare versions through 0.04 for Perl will hang in an infinite loop when parsing malformed attributes.
The parserc_parse function never advances the attribute-parse state cursor on certain malformed attribute forms, looping forever.
Nameless attributes such as "<a ='c'>" or unbalanced quotes "<a b='''''''c'>" can trigger this condition.
Note that the latest version available on CPAN is version 0.02. Newer versions are available on the git repository. |
| XML::Bare versions through 0.53 for Perl will hang in an infinite loop when parsing malformed attributes.
The parserc_parse function never advances the attribute-parse state cursor on certain malformed attribute forms, looping forever.
Nameless attributes such as "<a ='c'>" or unbalanced quotes "<a b='''''''c'>" can trigger this condition. |
| A flaw was found in libcupsfilters. The cfIEEE1284NormalizeMakeModel() function enters an infinite loop when processing a printer-advertised IEEE-1284 device ID with an empty model field, causing sustained CPU consumption. A network-adjacent attacker could exploit this by broadcasting a specially crafted printer advertisement, leading to denial of service. |
| Loop with unreachable exit condition ('infinite loop') in Active Directory Federation Services (AD FS) allows an unauthorized attacker to deny service over a network. |
| Loop with unreachable exit condition ('infinite loop') in Active Directory Federation Services (AD FS) allows an unauthorized attacker to deny service over a network. |
| Loop with unreachable exit condition ('infinite loop') in Azure Active Directory allows an unauthorized attacker to deny service over a network. |
| protobufjs compiles protobuf definitions into JavaScript (JS) functions. Prior to 7.6.5 and 8.6.6, protobufjs parsed option names by advancing through schema tokens until reaching an = token without checking for end of input, so a crafted .proto schema that opens an option declaration and ends prematurely can cause parse, Root.load, or Root.loadSync to loop indefinitely. This issue is fixed in versions 7.6.5 and 8.6.6. |
| OpenMcdf is a fully .NET / C# library to manipulate Compound File Binary File Format files, also known as Structured Storage. In 3.1.3 and earlier, the BST name-lookup loop in DirectoryTree.TryGetDirectoryEntry (OpenMcdf/DirectoryTree.cs:35-46) walks directory entries by repeatedly calling directories.TryGetSibling(child, siblingType, validateColor). A crafted CFB file with cyclic Left/Right sibling links among directory entries, constructed so the per-step BST-order check in TryGetSibling (DirectoryEntries.cs:84-85) is satisfied at every step, drives this while (child is not null) loop forever. There is no cycle detection in TryGetDirectoryEntry, and the bug is reachable from RootStorage.OpenStorage(name), TryOpenStorage(name), OpenStream(name), and TryOpenStream(name), causing an unrecoverable denial of service. This issue is fixed in version 3.1.4. |
| IBM Db2 11.5.0 through 11.5.9, and 12.1.0 through 12.1.4 is vulnerable to a trap when compiling a specially crafted statements containing subqueries could lead to a denial of service. |
| xrdp is an open source RDP server. In versions 0.10.6 and prior, a n issue was discovered where the software fails to properly validate the totalLength field within the RDP protocol control header during packet reception. An unauthenticated remote attacker can exploit this vulnerability by sending a specially crafted packet that forces the xrdp process or thread into an infinite, CPU-bound loop. Because the internal pointer fails to advance and the deadlock prevention mechanism is bypassed for specific protocol data unit types, the process consumes excessive CPU resources indefinitely. This can render the xrdp service unavailable and potentially lead to system-wide resource exhaustion if multiple malicious connections are established. This issue has been fixed in version 0.10.6.1. |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: iwlwifi: mld: stop TX during firmware restart
When iwlwifi firmware crashes (e.g., NMI_INTERRUPT_UNKNOWN on Intel
BE201/Wi-Fi 7), iwl_mld_nic_error() sets mld->fw_status.in_hw_restart
to true. However, iwl_mld_tx_from_txq() does not check this flag before
dequeuing frames from mac80211 and pushing them to the transport layer.
Since the firmware is dead, iwl_trans_tx() returns -EIO for each frame,
which then gets freed immediately. Under high-throughput conditions
(e.g., Tailscale UDP traffic or active SSH sessions), this creates a
tight dequeue-send-fail-free loop that wastes CPU cycles and generates
rapid skb allocation churn, leading to memory pressure from slab
fragmentation.
The RX path already has this guard (iwl_mld_rx_mpdu checks
in_hw_restart at rx.c:1906), and so does the TXQ allocation worker
(iwl_mld_add_txqs_wk at tx.c:156). Add the same guard to
iwl_mld_tx_from_txq() to stop all TX during firmware restart.
Frames left in mac80211's TXQs are naturally drained after restart
completes, when queue reallocation triggers iwl_mld_tx_from_txq()
via iwl_mld_add_txq_list(), or when new upper-layer traffic invokes
wake_tx_queue.
Tested on ASUS Zenbook 14 UX3405CA with Intel BE201 (Wi-Fi 7) on
kernel 6.19.5 where the firmware crashes approximately every 10-15
minutes under Tailscale traffic. |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: cfg80211: advance loop vars in cfg80211_merge_profile()
cfg80211_merge_profile() reassembles a Multi-BSSID non-transmitted BSS
profile that has been split across multiple consecutive MBSSID elements.
Its while-loop calls
cfg80211_get_profile_continuation(ie, ielen, mbssid_elem, sub_elem)
but never advances mbssid_elem or sub_elem inside the body. Each
iteration therefore searches for a continuation that follows the same
fixed pair; the helper returns the same next_mbssid; and the same
next_sub bytes are memcpy()'d into merged_ie at a growing offset until
the buffer fills.
Advance both mbssid_elem and sub_elem to the just-consumed continuation
so the next call to cfg80211_get_profile_continuation() searches for a
further continuation beyond it (or returns NULL when none exists).
A specially-crafted malicious beacon can take advantage of this bug
to cause the kernel to spend an excessive amount of time in
cfg80211_merge_profile (up to as much as 2ms per beacon received),
which could theoretically be abused in some way. |
| In the Linux kernel, the following vulnerability has been resolved:
l2tp: use list_del_rcu in l2tp_session_unhash
An unprivileged local user can pin a host CPU indefinitely in
l2tp_session_get_by_ifname() by issuing L2TP_CMD_SESSION_GET on
L2TP_ATTR_IFNAME concurrently with L2TP_CMD_SESSION_CREATE and
L2TP_CMD_SESSION_DELETE on the same tunnel. All three commands take
GENL_UNS_ADMIN_PERM, so CAP_NET_ADMIN in the netns user namespace
suffices; on any host that has l2tp_core loaded the trigger is
reachable from a standard `unshare -Urn` sandbox.
l2tp_session_unhash() removes a session from tunnel->session_list
with list_del_init(), but that list is walked by
l2tp_session_get_by_ifname() with list_for_each_entry_rcu() under
rcu_read_lock_bh(). list_del_init() leaves the deleted entry's
next/prev self-pointing; a reader that has loaded the entry and
then advances pos->list.next reads &session->list, container_of()s
back to the same session, and list_for_each_entry_rcu() never
reaches the list head. The CPU stays in strcmp() inside the
walker, with BH and preemption disabled, so RCU grace periods on
the host stall behind it and the wedged thread cannot be killed
(SIGKILL is delivered on syscall return).
Use list_del_rcu() to match the existing list_add_rcu() in
l2tp_session_register(); the deleted session remains visible to
in-flight walkers with consistent next/prev pointers until
kfree_rcu() in l2tp_session_free() releases it. tunnel->session_list
has exactly one list_del_init() call site; the list_del_init
(&session->clist) at l2tp_core.c:533 operates on the per-collision
list, which is not walked under RCU. list_empty(&session->list) is
not used anywhere in net/l2tp/ after the unhash point, so dropping
the post-delete self-init is safe; the fix has no userspace-visible
behavior change. |
| barebox version prior to 2026.04.0 contains a denial-of-service vulnerability in ext4 directory parsing in fs/ext4/ext4_common.c where the ext4fs_iterate_dir() function fails to validate that directory entry length values are non-zero. Attackers can supply a malicious ext4 filesystem image with a crafted directory entry containing a direntlen value of 0 to cause an infinite loop during directory listing or path resolution, resulting in the boot process hanging indefinitely. |
| Dasel is a command-line tool and library for querying, modifying, and transforming data structures. From 3.0.0 until 3.10.1, the selector lexer matchRegexPattern closure in (*Tokenizer).parseCurRune in selector/lexer/tokenize.go loops while tokenizing an unterminated regex literal such as r/ because peekRuneEqual returns false after the end of input, allowing attacker-controlled selector strings to consume CPU indefinitely. This issue is fixed in version 3.10.1. |
| Pillow is a Python imaging library. From 12.0.0 through 12.2.0, Pillow's EPS parser in PIL/EpsImagePlugin.py accepts a negative byte count in the %%BeginBinary directive, allowing a crafted EPS file to cause Image.open() to seek backwards to the same directive and parse it repeatedly in an infinite loop. This issue is fixed in version 12.3.0. |
| image-size through 2.0.2 contains a denial of service vulnerability that allows remote attackers to permanently block the Node.js event loop by supplying a specially crafted ICNS image buffer. Attackers can craft an ICNS buffer containing valid magic bytes and a zero-valued entry length field to trigger an infinite loop in the ICNS parser, as the offset is never incremented when the entry length field is 0, causing the while loop condition to remain true indefinitely. |
| image-size through 2.0.2 contains a denial of service vulnerability that allows remote attackers to permanently block the Node.js event loop by supplying a specially crafted image buffer with a zero-valued size field in a recognized box-type. Attackers can trigger an infinite loop in the JXL or HEIF image parsers by providing a crafted image containing a box with a size of zero, causing the offset to never advance and permanently hanging the application. |
| Loop with unreachable exit condition ('infinite loop') in Windows Active Directory allows an unauthorized attacker to deny service over a network. |
