CVE-2025-38709: linux
Vulnerability summary
CVE-2025-38709 is a medium (CVSS 5.5) vulnerability in linux. EPSS estimates a 0.15% chance of exploitation in the next 30 days, higher than 3.6% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 28 · Related 26Timeline
- 04-09-2025PublishedVulnerability first disclosed.
- 11-05-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
3 scores · 3 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.15%
Chance of exploitation in the next 30 days
Percentile
4%
Versus all other CVEs
30-day change
0.00 pp
From 0.15% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeNo weakness data has been published for this record.
Affected systems
Ubuntu149 products
- linuxAll versions (No fix recorded) | < 6.8.0-106.106
- linux-allwinner-5.19All versions (No fix recorded)
- linux-awsAll versions (No fix recorded) | < 6.8.0-1050.53
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Linux2 products
- linux≥ 89e4fdecb51cf5535867026274bc97de9480ade5, < 457d2c5e112fd08dc1039b1ae39a83ec1782360d | ≥ 89e4fdecb51cf5535867026274bc97de9480ade5, < 139a000d20f2f38ce34296feddd641d730fe1c08 | ≥ 89e4fdecb51cf5535867026274bc97de9480ade5, < b928438cc87c0bf7ae078e4b7b6e14261e84c5c5 | ≥ 89e4fdecb51cf5535867026274bc97de9480ade5, < 5d67b30aefeb7a949040bbb1b4e3b84c5d29a624 | ≥ 89e4fdecb51cf5535867026274bc97de9480ade5, < 7e49538288e523427beedd26993d446afef1a6fb | 4.14
- linux_kernel< 6.6.109 | ≥ 6.7, < 6.12.43 | ≥ 6.13, < 6.15.11 | ≥ 6.16, < 6.16.2
Debian1 product
- linuxAll versions (No fix recorded) | < 6.12.43-1 | < 6.16.3-1
3 vendors · 152 products
