Answer in brief
CVE-2025-38709 records a Medium severity (CVSS 5.5) vulnerability in loop: Avoid updating block size under exclusive owner. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=89e4fdecb51cf5535867026274bc97de9480ade5 <46034518cae95db4abfde990c9ca1a0751855072 || >=89e4fdecb51cf5535867026274bc97de9480ade5 <457d2c5e112fd08dc1039b1ae39a83ec1782360d || >=89e4fdecb51cf5535867026274bc97de9480ade5 <139a000d20f2f38ce34296feddd641d730fe1c08 || >=89e4fdecb51cf5535867026274bc97de9480ade5 <b928438cc87c0bf7ae078e4b7b6e14261e84c5c5 || >=89e4fdecb51cf5535867026274bc97de9480ade5 <5d67b30aefeb7a949040bbb1b4e3b84c5d29a624 || >=89e4fdecb51cf5535867026274bc97de9480ade5 <7e49538288e523427beedd26993d446afef1a6fb | 46034518cae95db4abfde990c9ca1a0751855072, 457d2c5e112fd08dc1039b1ae39a83ec1782360d, 139a000d20f2f38ce34296feddd641d730fe1c08, b928438cc87c0bf7ae078e4b7b6e14261e84c5c5, 5d67b30aefeb7a949040bbb1b4e3b84c5d29a624, 7e49538288e523427beedd26993d446afef1a6fb |
| Linux/Linuxgeneric | 4.14 | Not reported |
Published upstream
Sep 4, 2025
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 30, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 28, 2026
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.
Quoted source text, attributed separately from HOL analysis.