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Fencer Vulns
high 7.8

CVE-2026-31716 json

fs/ntfs3: validate rec->used in journal-replay file record check

published 2026-05-01 6 mo ago modified 2026-08-05 3 mo ago also EUVD-2026-26525

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 2%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

fs/ntfs3: validate rec->used in journal-replay file record check

check_file_record() validates rec->total against the record size but never validates rec->used. The do_action() journal-replay handlers read rec->used from disk and use it to compute memmove lengths:

DeleteAttribute: memmove(attr, ..., used - asize - roff) CreateAttribute: memmove(..., attr, used - roff) change_attr_size: memmove(..., used - PtrOffset(rec, next))

When rec->used is smaller than the offset of a validated attribute, or larger than the record size, these subtractions can underflow allowing us to copy huge amounts of memory in to a 4kb buffer, generally considered a bad idea overall.

This requires a corrupted filesystem, which isn't a threat model the kernel really needs to worry about, but checking for such an obvious out-of-bounds value is good to keep things robust, especially on journal replay

Fix this up by bounding rec->used correctly.

This is much like commit b2bc7c44ed17 ("fs/ntfs3: Fix slab-out-of-bounds read in DeleteIndexEntryRoot") which checked different values in this same switch statement.

Patch / fix

  • Linux Linux 5.15.209, 6.1.175, 6.6.136, 6.12.84, 6.18.25, 7.0.2, 7.1
  • linux Debian 12 6.1.176-1
  • linux Debian 13 6.12.85-1
  • linux Debian 14 7.0.3-1

debian advisories DEBIAN-CVE-2026-31716

  • linux Ubuntu 22.04 LTS 5.15.0-186.196
  • linux Ubuntu 24.04 LTS 6.8.0-136.136
  • linux Ubuntu 26.04 LTS 7.0.0-27.27
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1112.119
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1061.64
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1008.8
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1112.122
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1064.72

ubuntu advisories UBUNTU-CVE-2026-31716

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel-source openSUSE Tumbleweed 7.0.7-1.1

opensuse advisories openSUSE-SU-2026:10793-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-31716 updated

kernel: fs/ntfs3: validate rec->used in journal-replay file record check

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernel
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.13% chance of exploitation in the next 30 days, higher than 2% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Weakness
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.