CVE-2024-53234: erofs: handle NONHEAD !delta[1] lclusters gracefully

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-12-27 · updated 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: erofs: handle NONHEAD !delta[1] lclusters gracefully syzbot reported a WARNING in iomap_iter_done: iomap_fiemap+0x73b/0x9b0 fs/iomap/fiemap.c:80 ioctl_fiemap fs/ioctl.c:220 [inline] Generally, NONHEAD lclusters won't have delta[1]==0, except for crafted images and filesystems created by pre-1.0 mkfs versions. Previously, it would immediately bail out if delta[1]==0, which led to inadequate decompressed lengths (thus FIEMAP is impacted). Treat it as delta[1]=1 to work around these legacy mkfs versions. `lclusterbits > 14` is illegal for compact indexes, error out too.

Affected products

Linux kernel: from 5.4.251 before 5.5; from 5.10.188 before 5.11; from 5.15 before 6.1.127; from 6.2 before 6.6.64; from 6.7 before 6.11.11; from 6.12 before 6.12.2 — fixed in 5.11, 5.5, 6.1.127, 6.11.11, 6.12.2, 6.6.64

How to fix

Upgrade to a fixed version: Linux kernel 5.11, 5.5, 6.1.127, 6.11.11. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2024-53234 or the next vulnerability affects your stack