CVE-2024-26601: ext4: regenerate buddy after block freeing failed if under fc replay

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-02-26 · updated 2026-08-04

Description

In the Linux kernel, the following vulnerability has been resolved: ext4: regenerate buddy after block freeing failed if under fc replay This mostly reverts commit 6bd97bf273bd ("ext4: remove redundant mb_regenerate_buddy()") and reintroduces mb_regenerate_buddy(). Based on code in mb_free_blocks(), fast commit replay can end up marking as free blocks that are already marked as such. This causes corruption of the buddy bitmap so we need to regenerate it in that case.

Affected products

Linux kernel: before 5.10.211; from 5.11.0 before 5.15.150; from 5.16.0 before 6.1.78; from 6.2.0 before 6.6.17; from 6.7.0 before 6.7.5 — fixed in 5.10.211, 5.15.150, 6.1.78, 6.6.17, 6.7.5

How to fix

Upgrade to a fixed version: Linux kernel 5.10.211, 5.15.150, 6.1.78, 6.6.17. Check the vendor advisory for mitigations.

References

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