CVE-2025-38709 (GCVE-0-2025-38709)

Vulnerability from cvelistv5 – Published: 2025-09-04 15:32 – Updated: 2026-05-11 21:33
VLAI
Title
loop: Avoid updating block size under exclusive owner
Summary
In the Linux kernel, the following vulnerability has been resolved: loop: Avoid updating block size under exclusive owner Syzbot came up with a reproducer where a loop device block size is changed underneath a mounted filesystem. This causes a mismatch between the block device block size and the block size stored in the superblock causing confusion in various places such as fs/buffer.c. The particular issue triggered by syzbot was a warning in __getblk_slow() due to requested buffer size not matching block device block size. Fix the problem by getting exclusive hold of the loop device to change its block size. This fails if somebody (such as filesystem) has already an exclusive ownership of the block device and thus prevents modifying the loop device under some exclusive owner which doesn't expect it.
Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 7056 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 89e4fdecb51cf5535867026274bc97de9480ade5 , < 457d2c5e112fd08dc1039b1ae39a83ec1782360d (git)
Affected: 89e4fdecb51cf5535867026274bc97de9480ade5 , < 139a000d20f2f38ce34296feddd641d730fe1c08 (git)
Affected: 89e4fdecb51cf5535867026274bc97de9480ade5 , < b928438cc87c0bf7ae078e4b7b6e14261e84c5c5 (git)
Affected: 89e4fdecb51cf5535867026274bc97de9480ade5 , < 5d67b30aefeb7a949040bbb1b4e3b84c5d29a624 (git)
Affected: 89e4fdecb51cf5535867026274bc97de9480ade5 , < 7e49538288e523427beedd26993d446afef1a6fb (git)
guessed Create a notification for this product.
Linux Linux Affected: 4.14
Unaffected: 0 , < 4.14 (semver)
Unaffected: 6.6.109 , ≤ 6.6.* (semver)
Unaffected: 6.12.43 , ≤ 6.12.* (semver)
Unaffected: 6.15.11 , ≤ 6.15.* (semver)
Unaffected: 6.16.2 , ≤ 6.16.* (semver)
Unaffected: 6.17 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
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}



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