VulnerabilityPublished 22 Apr 2026Updated 5 Nov 2026

CVE-2026-31438: Linux kernel · netfs: Fix kernel BUG in netfs_limit_iter() for ITER_KVEC iterators

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in 67e467a11f62ff64ad219dc6aa5459e132c79d14 : update Linux kernel when convenient.

Data as of 5 Nov 2026, 21:49 UTC

Severity

Unrated

Rated by Threat Radar · 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, 2026-11-05.

Patch

Available – fixed in 67e467a11f62ff64ad219dc6aa5459e132c79d14, 18c2e20b42dd21db599e42d05ddaeeb647b2bb6d, 4bc2d72c7695cedf6d4e1a558924903c2b28a78e +1

Exploitation evidence

Disclosed: evidence found.
CVE published 22 Apr 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 5 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 Linux kernel to 67e467a11f62ff64ad219dc6aa5459e132c79d14, 18c2e20b42dd21db599e42d05ddaeeb647b2bb6d, 4bc2d72c7695cedf6d4e1a558924903c2b28a78e or 00d6df7115f6972370974212de9088087820802e.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ cae932d3aee55035a54415dcea8e7ecf2ec469b5, < 67e467a11f62ff64ad219dc6aa5459e132c79d14	Fixed in 67e467a11f62ff64ad219dc6aa5459e132c79d14
LinuxLinux	Affected ≥ cae932d3aee55035a54415dcea8e7ecf2ec469b5, < 18c2e20b42dd21db599e42d05ddaeeb647b2bb6d	Fixed in 18c2e20b42dd21db599e42d05ddaeeb647b2bb6d
LinuxLinux	Affected ≥ cae932d3aee55035a54415dcea8e7ecf2ec469b5, < 4bc2d72c7695cedf6d4e1a558924903c2b28a78e	Fixed in 4bc2d72c7695cedf6d4e1a558924903c2b28a78e
LinuxLinux	Affected ≥ cae932d3aee55035a54415dcea8e7ecf2ec469b5, < 00d6df7115f6972370974212de9088087820802e	Fixed in 00d6df7115f6972370974212de9088087820802e
LinuxLinux	Affected =6.8	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: netfs: Fix kernel BUG in netfs_limit_iter() for ITER_KVEC iterators When a process crashes and the kernel writes a core dump to a 9P filesystem, __kernel_write() creates an ITER_KVEC iterator. This iterator reaches netfs_limit_iter() via netfs_unbuffered_write(), which only handles ITER_FOLIOQ, ITER_BVEC and ITER_XARRAY iterator types, hitting the BUG() for any other type. Fix this by adding netfs_limit_kvec() following the same pattern as netfs_limit_bvec(), since both kvec and bvec are simple segment arrays with pointer and length fields. Dispatch it from netfs_limit_iter() when the iterator type is ITER_KVEC.

References

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