The mbcache feature in the ext2 and ext4 filesystem implementations in the Linux kernel before 4.6 mishandles xattr block caching, which allows local users to cause a denial of service (soft lockup) via filesystem operations in environments that use many attributes, as demonstrated by Ceph and Samba.
Severity
CVSS 3.0
5.5 medium
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS
0.5% chance of exploitation in the next 30 days; higher than 39% of CVEs (scores of 2026-10-31)