CVE-2025-21736: nilfs2: fix possible int overflows in nilfs_fiemap()

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-02-27 · updated 2026-06-17
Weakness: CWE-190

Description

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.

Affected products

Linux kernel: from 2.6.38 before 6.1.129; from 6.2 before 6.6.78; from 6.7 before 6.12.14; from 6.13 before 6.13.3 — fixed in 6.1.129, 6.12.14, 6.13.3, 6.6.78

How to fix

Upgrade to a fixed version: Linux kernel 6.1.129, 6.12.14, 6.13.3, 6.6.78. Check the vendor advisory for mitigations.

References

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