CVE-2025-38709loop: Avoid updating block size under exclusive owner
- 5.5MediumCVSS base score
- 0.16%Exploitation in 30 daysEPSS · top 95% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
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.
Timeline
ID reserved
By Linux
- 5 months later
· 5 months later
Published
- 14 months later
· 14 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.1 | Medium5.5 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.16% · top 95% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.5.
Affected products
- affected 89e4fdecb51cf5535867026274bc97de9480ade5 – < 46034518cae95db4abfde990c9ca1a0751855072
- affected 89e4fdecb51cf5535867026274bc97de9480ade5 – < 457d2c5e112fd08dc1039b1ae39a83ec1782360d
- affected 89e4fdecb51cf5535867026274bc97de9480ade5 – < 139a000d20f2f38ce34296feddd641d730fe1c08
- affected 89e4fdecb51cf5535867026274bc97de9480ade5 – < b928438cc87c0bf7ae078e4b7b6e14261e84c5c5
- affected 89e4fdecb51cf5535867026274bc97de9480ade5 – < 5d67b30aefeb7a949040bbb1b4e3b84c5d29a624
- affected 89e4fdecb51cf5535867026274bc97de9480ade5 – < 7e49538288e523427beedd26993d446afef1a6fb
- affected 4.14
- unaffected < 4.14
- unaffected 6.1.191 – ≤ 6.1.*
- unaffected 6.6.109 – ≤ 6.6.*
- unaffected 6.12.43 – ≤ 6.12.*
- unaffected 6.15.11 – ≤ 6.15.*
- unaffected 6.16.2 – ≤ 6.16.*
- unaffected 6.17 – ≤ *
References
References6
- https://git.kernel.org/stable/c/46034518cae95db4abfde990c9ca1a0751855072 (opens in a new tab)
- https://git.kernel.org/stable/c/457d2c5e112fd08dc1039b1ae39a83ec1782360d (opens in a new tab)
- https://git.kernel.org/stable/c/139a000d20f2f38ce34296feddd641d730fe1c08 (opens in a new tab)
- https://git.kernel.org/stable/c/b928438cc87c0bf7ae078e4b7b6e14261e84c5c5 (opens in a new tab)
- https://git.kernel.org/stable/c/5d67b30aefeb7a949040bbb1b4e3b84c5d29a624 (opens in a new tab)
- https://git.kernel.org/stable/c/7e49538288e523427beedd26993d446afef1a6fb (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2025-26760 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2025-38709)Record last updated .