CVE-2026-31449: Linux Kernel

High severity, CVSS 7.8. EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: ext4: validate p_idx bounds in ext4_ext_correct_indexes ext4_ext_correct_indexes() walks up the extent tree correcting index entries when the first extent in a leaf is modified. Before accessing path[k].p_idx->ei_block, there is no validation that p_idx falls within the valid range of index entries for that level. If the on-disk extent header contains a corrupted or crafted eh_entries value, p_idx can point past the end of the allocated buffer, causing a slab-out-of-bounds read. Fix this by validating path[k].p_idx against EXT_LAST_INDEX() at both access sites: before the while loop and inside it. Return -EFSCORRUPTED if the index pointer is out of range, consistent with how other bounds violations are handled in the ext4 extent tree code.

Affected products

• Linux Linux Kernel: from 2.6.19.1, before 6.12.80 (fixed in 6.12.80); from 6.13, before 6.18.21 (fixed in 6.18.21); from 6.19, before 6.19.11 (fixed in 6.19.11); version 2.6.19 only; version 7.0 only

Published 2026-04-22. Last modified 2026-09-08.