CVE-2026-64538: Linux kernel · ipv6: Fix null-ptr-deref in fib6_nh_mtu_change().
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 3 Nov 2026, 18:32 UTC
Rated Medium by Threat Radar's AI analysis · No CVSS score from NVD or the CNA
Thin evidence
One scorer or noneExploitation evidence
Disclosed: evidence found.
CVE published 27 Jul 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 3 Nov 2026.
What to do
AI-suggested
A fix has been applied in the Linux kernel source to add a NULL check in fib6_nh_mtu_change(), preventing the null pointer dereference. Users should update their Linux kernel to a version that includes this fix once available. Patch status is not explicitly confirmed in the provided data; check the official Linux kernel advisories for the fixed version and apply updates accordingly.
Description
A null pointer dereference vulnerability in the Linux kernel's IPv6 implementation was fixed in the function fib6_nh_mtu_change(). The issue arises because the function dereferences a pointer without checking for NULL, leading to a potential kernel oops (crash). This occurs during an MTU update walk triggered by router advertisement processing when certain network device pointers have been cleared. The fix adds a NULL check to prevent the dereference.
References
- git.kernel.org/stable/c/d08d019f2f43a6f9a71e81868bbc326b3afaf37b (opens in a new tab)
- git.kernel.org/stable/c/1451deca9896957159f0666520a792c1b861af4f (opens in a new tab)
- git.kernel.org/stable/c/b2c70dd3326809429b709a9c7e9220d29923051a (opens in a new tab)
- git.kernel.org/stable/c/302d57ed7872838b40e56a868fb4c7da7da606e9 (opens in a new tab)
- git.kernel.org/stable/c/80600b5d0f3ecb9324120dc95b5e915130f516c5 (opens in a new tab)
- git.kernel.org/stable/c/b0d0eb13a0441a8ebf4f227843deaf494f1e2c33 (opens in a new tab)
- git.kernel.org/stable/c/6428634f7a0b7878144b4925c37856bef3224967 (opens in a new tab)
- git.kernel.org/stable/c/46c3b8191aad3d032776bf3bebf03efdf5f4b905 (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)