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Fencer Vulns
medium 5.5

CVE-2025-21736 json

nilfs2: fix possible int overflows in nilfs_fiemap()

published 2025-02-27 20 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-5178

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 17%
public exploits
0
none known

Summary

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

nilfs2: fix possible int overflows in nilfs_fiemap()

Since nilfs_bmap_lookup_contig() in nilfs_fiemap() calculates its result by being prepared to go through potentially maxblocks == INT_MAX blocks, the value in n may experience an overflow caused by left shift of blkbits.

While it is extremely unlikely to occur, play it safe and cast right hand expression to wider type to mitigate the issue.

Found by Linux Verification Center (linuxtesting.org) with static analysis tool SVACE.

Patch / fix

  • Linux Linux 5.4.291, 5.10.235, 5.15.179, 6.1.129, 6.6.78, 6.12.14, 6.13.3, 6.14
  • linux Debian 12 6.1.129-1
  • linux Debian 14, Debian 13 6.12.15-1

debian advisories DEBIAN-CVE-2025-21736

  • linux Ubuntu 20.04 LTS 5.4.0-216.236
  • linux Ubuntu 22.04 LTS 5.15.0-140.150
  • linux Ubuntu 24.04 LTS 6.8.0-64.67
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1146.156
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1084.91
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1032.34
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1149.158
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1083.92

ubuntu advisories UBUNTU-CVE-2025-21736

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-coco SLE Module for Confidential Computing Technical Preview 15 SP6 6.4.0-15061.21.coco15sp6.1
  • kernel-syms-coco SLE Module for Confidential Computing Technical Preview 15 SP6 6.4.0-15061.21.coco15sp6.1
  • kernel-coco_debug SLE Module for Confidential Computing Technical Preview 15 SP6 6.4.0-15061.21.coco15sp6.1
  • kernel-source-coco SLE Module for Confidential Computing Technical Preview 15 SP6 6.4.0-15061.21.coco15sp6.1
  • kernel-source Linux Micro 6.1, Linux Micro 6.0 6.4.0-28.1
  • kernel-default Linux Micro 6.1, Linux Micro 6.0 6.4.0-28.1
  • kernel-kvmsmall Linux Micro 6.1, Linux Micro 6.0 6.4.0-28.1
  • kernel-default-base Linux Micro 6.1, Linux Micro 6.0 6.4.0-28.1.21.6

suse advisories SUSE-SU-2025:01919-1SUSE-SU-2025:20192-1SUSE-SU-2025:20270-1SUSE-SU-2025:20190-1SUSE-SU-2025:20260-1SUSE-SU-2025:1180-1

  • kernel CBL-Mariner 2.0 5.15.179.1-1

azure linux advisories AZL-57832

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

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-2025-21736 updated cvss 5.5

kernel: nilfs2: fix possible int overflows in nilfs_fiemap()

  • 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

0.25% chance of exploitation in the next 30 days, higher than 17% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

Classification

Weakness
  • CWE-190 Integer Overflow or Wraparound
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.