CVE-2026-31674: Linux kernel · netfilter: ip6t_rt: reject oversized addrnr in rt_mt6_check()
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 7.1 High · fixed in ded71f5684df16fa645cca5bf4fe6b0cd8a46119 : patch Linux kernel soon.
Data as of 26 Oct 2026, 17:30 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 ded71f5684df16fa645cca5bf4fe6b0cd8a46119, d8795fde1f78669a87c87ac29fceab2f104daa8c, c6a503a9f4debc654e3a6a7ca1f7fce6a9953c59 +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 is available and has been applied in the Linux kernel. Users should update to a fixed kernel version that includes the patches identified by the commit hashes provided in the established facts. Since this is a kernel-level vulnerability, applying the official kernel updates from the Linux vendor or distribution is the recommended remediation. No additional mitigations are indicated by the vendor advisory.
Description
CVE-2026-31674 is a high-severity vulnerability in the Linux kernel's netfilter subsystem, specifically in the ip6t_rt module. The flaw involves improper validation of the addrnr parameter in the rt_mt6_check() function, which can lead to out-of-bounds access. This vulnerability has been addressed by rejecting rules where addrnr exceeds the allowed IP6T_RT_HOPS limit during rule installation, preventing malformed rules from causing memory safety issues.
References
- git.kernel.org/stable/c/13e3e30ed3b5b67cc1db2bd58a5d09b0f07debfa (opens in a new tab)
- git.kernel.org/stable/c/af9b7e2b765966457f4ec23be5bd34a141f89574 (opens in a new tab)
- git.kernel.org/stable/c/29ea965a1353bc8303877422f79c8211e9ba9c55 (opens in a new tab)
- git.kernel.org/stable/c/c6a503a9f4debc654e3a6a7ca1f7fce6a9953c59 (opens in a new tab)
- git.kernel.org/stable/c/ded71f5684df16fa645cca5bf4fe6b0cd8a46119 (opens in a new tab)
- git.kernel.org/stable/c/d8795fde1f78669a87c87ac29fceab2f104daa8c (opens in a new tab)
- git.kernel.org/stable/c/a28ebf6f99de270d6338ccdc3b49f3e818f99b7b (opens in a new tab)
- git.kernel.org/stable/c/9d3f027327c2fa265f7f85ead41294792c3296ed (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-082556.html (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-019113.html (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-457936.html (opens in a new tab)