CVE-2025-38709

MEDIUM EPSS 3.4%
Published Sep 4, 20259mo ago · Modified Jun 17, 20261w ago
5.5 CVSS 3.1
Medium
Find Similar
Published Sep 4, 2025 9mo ago
Last Modified Jun 17, 2026 1w ago

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 Details

Base Score
5.5
Exploitability
1.8
Impact
3.6
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

EPSS Exploit Probability
3.4% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Affected Products 4

VendorProductVersionRange
linuxlinux_kernel* <6.6.109
linuxlinux_kernel*≥6.7  –  <6.12.43
linuxlinux_kernel*≥6.13  –  <6.15.11
linuxlinux_kernel*≥6.16  –  <6.16.2

References 5

  • git.kernel.org https://git.kernel.org/stable/c/139a000d20f2f38ce34296feddd641d730fe1c08
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/457d2c5e112fd08dc1039b1ae39a83ec1782360d
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/5d67b30aefeb7a949040bbb1b4e3b84c5d29a624
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/7e49538288e523427beedd26993d446afef1a6fb
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/b928438cc87c0bf7ae078e4b7b6e14261e84c5c5
    Patch

Remediation

  • git.kernel.org https://git.kernel.org/stable/c/139a000d20f2f38ce34296feddd641d730fe1c08
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/457d2c5e112fd08dc1039b1ae39a83ec1782360d
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/5d67b30aefeb7a949040bbb1b4e3b84c5d29a624
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/7e49538288e523427beedd26993d446afef1a6fb
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/b928438cc87c0bf7ae078e4b7b6e14261e84c5c5
    Patch