CVE-2022-50782: 
Linux Kernel vulnerability analysis and mitigation

CVE-2022-50782 is a Linux kernel vulnerability in the ext4 filesystem subsystem, specifically a bug (BUG_ON) triggered in __es_tree_search caused by a bad (corrupt or malformed) quota inode. The flaw was published on December 24, 2025, and affects the Linux kernel's ext4 extent status tree search logic. It has an EPSS score of 0.024% (low), and no CVSS score has been publicly assigned at this time (Feedly, Vulners).

The root cause is improper handling of a malformed or corrupt quota inode during ext4 filesystem mounting, which triggers a kernel BUG_ON assertion failure at fs/ext4/extents_status.c:202 in the __es_tree_search function (CWE-617: Reachable Assertion). The call chain leading to the crash involves ext4_quota_read → ext4_bread → ext4_getblk → ext4_map_blocks → ext4_ext_map_blocks → ext4_find_extent → ext4_cache_extents → ext4_es_cache_extent → __es_tree_search. The bug is reproducible during the mount operation when the kernel processes a specially crafted or corrupted ext4 image with a bad quota inode, causing an invalid opcode exception on affected kernels (Feedly).

Successful triggering of this vulnerability causes a kernel panic (BUG_ON assertion failure), resulting in a denial of service — the affected system crashes or becomes unresponsive. The impact is limited to availability; there is no evidence of confidentiality or integrity compromise. An attacker or unprivileged user with the ability to mount a crafted ext4 filesystem image could crash the host kernel, potentially affecting all processes and services running on the system (Feedly).

Apply the upstream Linux kernel patches that fix the __es_tree_search BUG_ON triggered by bad quota inodes in ext4. The fix has been backported to multiple stable kernel branches, with commits available at the kernel stable tree (e.g., 0dcbf4dc3d54, 1d5524832ff2, 1daff79463d7, 794c9175db1f, 98004f926d27). SUSE has issued an advisory (SUSE-2026:0411) addressing this vulnerability; users of affected distributions should apply the relevant kernel updates (Tenable, Linux Security). As a workaround, restrict unprivileged users from mounting ext4 filesystems (e.g., via nosuid/nodev mount policies or disabling user-namespace mounts).