CVE-2026-31679: Linux kernel · openvswitch: validate MPLS set/set_masked payload length
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 7.1 High · fixed in c1f97152df8dfb17e855ddf0fc409b7bd13e9700 : patch Linux kernel soon.
Data as of 26 Oct 2026, 13:37 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- 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, 2026-10-16.
- Patch
- Available – fixed in c1f97152df8dfb17e855ddf0fc409b7bd13e9700, bd50c7484c3bb34097571c1334174fb8b7408036, 546b68ac893595877ffbd7751e5c55fd1c43ede6 +5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 25 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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AI-suggested
A fix for this vulnerability is available and has been applied in multiple Linux kernel commits. Users should update their Linux kernel to a version that includes these fixes. Since this is not a cloud service, manual patching is required. There are no vendor advisories indicating that no action is needed or that the issue is already mitigated without patching.
Description
CVE-2026-31679 is a high-severity vulnerability in the Linux kernel's openvswitch component related to improper validation of MPLS set/set_masked action payload lengths. The vulnerability arises because the validate_set() function accepted variable-sized MPLS payloads, whereas fixed-size MPLS key data is expected. This flaw could allow malformed MPLS action payloads to be processed, potentially leading to denial of service or other impacts. The issue has been resolved by enforcing strict validation of MPLS payload lengths and rejecting invalid payloads early.
References
- git.kernel.org/stable/c/68f32ef0683c8d1c05cd2e4f16818fa63ff59c6f (opens in a new tab)
- git.kernel.org/stable/c/4cae986225f8b8679ad86b924918e7d75a96aa61 (opens in a new tab)
- git.kernel.org/stable/c/8ed7b9930cbc3bc71f868fa79a68700ac88d586a (opens in a new tab)
- git.kernel.org/stable/c/c1f97152df8dfb17e855ddf0fc409b7bd13e9700 (opens in a new tab)
- git.kernel.org/stable/c/98de18d327ef8cbbb704980e359e4872d8c28997 (opens in a new tab)
- git.kernel.org/stable/c/bd50c7484c3bb34097571c1334174fb8b7408036 (opens in a new tab)
- git.kernel.org/stable/c/2ca33b88a79ca42f017ae0f7011280325655438e (opens in a new tab)
- git.kernel.org/stable/c/546b68ac893595877ffbd7751e5c55fd1c43ede6 (opens in a new tab)