CVE-2026-31449: linux Out-of-bounds Read

Vulnerability summary

CVE-2026-31449 is a high (CVSS 7.8) Out-of-bounds Read vulnerability in linux. EPSS estimates a 0.15% chance of exploitation in the next 30 days, higher than 3.4% of scored vulnerabilities.

Timeline

1. 22-04-2026
   PublishedVulnerability first disclosed.
2. 19-10-2026
   Last modifiedVulnerability information updated.

Description

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.

• CWE-125Out-of-bounds ReadThe product reads data past the end, or before the beginning, of the intended buffer.