Medium (5.5) in linux linux kernel. EPSS 0.2% chance of exploitation in the next 30 days.
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.
Severity
CVSS 3.1
5.5 medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS
0.2% chance of exploitation in the next 30 days; higher than 11% of CVEs (scores of 2026-10-31)