# CVE-2026-31449

> Vulnerability · severity: **HIGH** (CVSS 7.8).

## 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.

## Key facts

- **CVE ID:** CVE-2026-31449
- **Published:** 2026-04-22
- **CVSS severity:** HIGH
- **CVSS base score:** 7.8
- **CWE codes:** CWE-125

## Affected products

- `linux:linux_kernel`

## Primary sources

- NIST NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31449

## Citation

> AI Analytics. CVE-2026-31449. Retrieved 2026-07-19 from https://api.ai-analytics.org/cve/CVE-2026-31449. Derived from NIST NVD. Licensed CC0.

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