VulnerabilityPublished 1 May 2026Updated 6 Nov 2026

CVE-2026-31752: Linux kernel · bridge: br_nd_send: validate ND option lengths

Affects Linux kernelSource CVE Database V5

Compare

Not known to be exploited · fixed in ee02d8991fd7bd86ed6ebd0deb4aab53feb0e43a : patch Linux kernel soon.

Data as of 6 Nov 2026, 16:33 UTC

Severity

High

Rated High by Threat Radar's AI analysis · No CVSS score from NVD or the CNA

Thin evidence

One scorer or none

Exploitation: No evidence of active exploitation and no public proof of concept
Automatable: Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact: Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-11-06.

Patch

Available – fixed in ee02d8991fd7bd86ed6ebd0deb4aab53feb0e43a, e71303a9190496136e240c4f2872b7b0b16027a7, e0bfd6d4dc77ab345b6c65eef0cfe9b2f69085aa +5

Exploitation evidence

Disclosed: evidence found.
CVE published 1 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ ed842faeb2bd49256f00485402f3113205f91d30, < ee02d8991fd7bd86ed6ebd0deb4aab53feb0e43a	Fixed in ee02d8991fd7bd86ed6ebd0deb4aab53feb0e43a
LinuxLinux	Affected ≥ ed842faeb2bd49256f00485402f3113205f91d30, < e71303a9190496136e240c4f2872b7b0b16027a7	Fixed in e71303a9190496136e240c4f2872b7b0b16027a7
LinuxLinux	Affected ≥ ed842faeb2bd49256f00485402f3113205f91d30, < e0bfd6d4dc77ab345b6c65eef0cfe9b2f69085aa	Fixed in e0bfd6d4dc77ab345b6c65eef0cfe9b2f69085aa
LinuxLinux	Affected ≥ ed842faeb2bd49256f00485402f3113205f91d30, < c49b9256bbacb6a135654aebd12e4c0e87166b7c	Fixed in c49b9256bbacb6a135654aebd12e4c0e87166b7c
LinuxLinux	Affected ≥ ed842faeb2bd49256f00485402f3113205f91d30, < 850837965af15707fd3142c1cf3c5bfaf022299b	Fixed in 850837965af15707fd3142c1cf3c5bfaf022299b
LinuxLinux	Affected ≥ ed842faeb2bd49256f00485402f3113205f91d30, < 837392a38445729c22e03d3abcf33f07763efd85	Fixed in 837392a38445729c22e03d3abcf33f07763efd85

AI-suggested

A fix is available and has been applied in specific Linux kernel commits. Users should update to a Linux kernel version that includes these fixes to remediate the vulnerability. Since this is not a cloud service, manual patching is required.

Description

A vulnerability in the Linux kernel's bridge component (br_nd_send function) allows improper validation of Neighbor Discovery (ND) option lengths. This flaw could cause the parser to read beyond the intended option boundaries or use an undersized source link-layer address option payload. The issue has been addressed by validating option lengths against the remaining option area and ensuring the source LLADDR is only read when the option size is sufficient.

Impact

Improper validation of ND option lengths could lead to out-of-bounds memory reads or processing of malformed packets within the Linux kernel's network bridge code. While the exact impact is not detailed, such flaws can potentially cause kernel crashes or memory corruption, affecting system stability and security.

Summary

The Linux kernel's br_nd_send() function processes Neighbor Discovery options based on lengths provided within those options. A malformed ND option could cause the parser to advance beyond the computed option span or use a source LLADDR option payload that is too short. The vulnerability is mitigated by adding validation to check option lengths against the remaining NS option area before advancing and by reading the source LLADDR only if the option is large enough to contain a full Ethernet address. This fix prevents potential out-of-bounds reads or malformed packet processing.

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 6 Nov 2026, 16:33 UTC

Technical details

References

Community reviews

Related threats