5.5

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

Analyzed
AliasesUBUNTU-CVE-2026-31438DEBIAN-CVE-2026-31438
Published 22-04-2026Last modified 11-05-2026

Vulnerability summary

CVE-2026-31438 is a medium (CVSS 5.5) NULL Pointer Dereference vulnerability in linux. EPSS estimates a 0.12% chance of exploitation in the next 30 days, higher than 1.9% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.5/10
010
Medium · v3.1 (NVD)
EPSS score
0.12%
0%100%
Low · -0.04 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 19 · Related 19
OPENSUSE-SU-2026:21388-1SUSE-SU-2026:22742-1SUSE-SU-2026:22769-1SUSE-SU-2026:22812-1SUSE-SU-2026:22835-1USN-8567-1

Timeline

  1. 22-04-2026
    PublishedVulnerability first disclosed.
  2. 11-05-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.12%

Chance of exploitation in the next 30 days

Percentile

2%

Versus all other CVEs

30-day change

Decrease -0.04 pp

From 0.16% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu130 products
  • linux< 6.8.0-136.136 | All versions (No fix recorded)
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-aws< 6.8.0-1061.64 | All versions (No fix recorded)
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Linux2 products
  • linux≥ cae932d3aee55035a54415dcea8e7ecf2ec469b5, < 18c2e20b42dd21db599e42d05ddaeeb647b2bb6d | ≥ cae932d3aee55035a54415dcea8e7ecf2ec469b5, < 4bc2d72c7695cedf6d4e1a558924903c2b28a78e | ≥ cae932d3aee55035a54415dcea8e7ecf2ec469b5, < 00d6df7115f6972370974212de9088087820802e | ≥ cae932d3aee55035a54415dcea8e7ecf2ec469b5, < 67e467a11f62ff64ad219dc6aa5459e132c79d14 | 6.8
  • linux_kernel≥ 6.8, < 6.12.80 | ≥ 6.13, < 6.18.21 | ≥ 6.19, < 6.19.11 | 7.0:rc1 | 7.0:rc2 | 7.0:rc3 | 7.0:rc4 | 7.0:rc5 | 7.0:rc6
Debian1 product
  • linux< 6.12.85-1 | < 6.19.11-1

3 vendors · 133 products

References

22 links
Show all 22 references