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Fencer Vulns
medium 5.5

CVE-2025-37858 json

fs/jfs: Prevent integer overflow in AG size calculation

published 2025-05-09 18 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-14134

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 24%
public exploits
0
none known

Summary

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

fs/jfs: Prevent integer overflow in AG size calculation

The JFS filesystem calculates allocation group (AG) size using 1 << l2agsize in dbExtendFS(). When l2agsize exceeds 31 (possible with >2TB aggregates on 32-bit systems), this 32-bit shift operation causes undefined behavior and improper AG sizing.

On 32-bit architectures: - Left-shifting 1 by 32+ bits results in 0 due to integer overflow - This creates invalid AG sizes (0 or garbage values) in sbi->bmap->db_agsize - Subsequent block allocations would reference invalid AG structures - Could lead to: - Filesystem corruption during extend operations - Kernel crashes due to invalid memory accesses - Security vulnerabilities via malformed on-disk structures

Fix by casting to s64 before shifting: bmp->db_agsize = (s64)1 << l2agsize;

This ensures 64-bit arithmetic even on 32-bit architectures. The cast matches the data type of db_agsize (s64) and follows similar patterns in JFS block calculation code.

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

Patch / fix

  • Linux Linux 5.4.293, 5.10.237, 5.15.181, 6.1.135, 6.6.88, 6.12.24, 6.13.12, 6.14.3, 6.15
  • linux Debian 12 6.1.135-1
  • linux Debian 14, Debian 13 6.12.25-1

debian advisories DEBIAN-CVE-2025-37858

  • linux Ubuntu 22.04 LTS 5.15.0-144.157
  • linux Ubuntu 24.04 LTS 6.8.0-100.100
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1088.95
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1046.49
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1087.96
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1047.50
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1085.91
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1043.48

ubuntu advisories UBUNTU-CVE-2025-37858

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 6.4.0-15061.28.coco15sp6.1
  • kernel-syms-coco SLE Module for Confidential Computing Technical Preview 15 SP6 6.4.0-15061.28.coco15sp6.1
  • kernel-coco_debug SLE Module for Confidential Computing Technical Preview 15 SP6 6.4.0-15061.28.coco15sp6.1
  • kernel-source-coco SLE Module for Confidential Computing Technical Preview 15 SP6 6.4.0-15061.28.coco15sp6.1
  • kernel-rt Real Time Module 15 SP7 6.4.0-150700.7.8.1
  • kernel-syms-rt Real Time Module 15 SP7 6.4.0-150700.7.8.1
  • kernel-source-rt Real Time Module 15 SP7 6.4.0-150700.7.8.1
  • kernel-64kb SLE Module for Basesystem 15 SP7 6.4.0-150700.53.6.1

suse advisories SUSE-SU-2025:02923-1SUSE-SU-2025:02333-1SUSE-SU-2025:02307-1SUSE-SU-2025:02254-1SUSE-SU-2025:02000-1SUSE-SU-2025:20413-1

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-2025-37858 updated cvss 5.5

kernel: fs/jfs: Prevent integer overflow in AG size calculation

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    affected: no fix planned “Out of support scope”
  • 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

0.31% chance of exploitation in the next 30 days, higher than 24% 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.