CVE-2026-31449
Published: April 23, 2026Last modified: April 23, 2026
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.
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 7.8 |
| Attack Vector | LOCAL |
| Attack complexity | LOW |
| Privileges required | NONE |
| User interaction | REQUIRED |
| Scope | UNCHANGED |
| Confidentiality | HIGH |
| Integrity impact | HIGH |
| Availability impact | HIGH |
| Vector | CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | linux-lts | Vulnerable (6.1.168-r0) |
| 25 LTS | linux-lts | Fixed (6.12.80-r0) | |
| Stream | linux-lts | Fixed (6.12.80-r0) |
References
- https://git.kernel.org/stable/c/01bf1e0b997d82c0e353b51ed74ef99698043c33
- https://git.kernel.org/stable/c/2acb5c12ebd860f30e4faf67e6cc8c44ddfe5fe8
- https://git.kernel.org/stable/c/407c944f217c17d4343148011acafebc604d55e1
- https://git.kernel.org/stable/c/4d08401aa13f1531216f1a7ae281ca4806e90a5c
- https://git.kernel.org/stable/c/93f2e975ed658ce09db4d4c2877ca2c06540df83