# CVE-2026-31659

> Vulnerability · severity: **CRITICAL** (CVSS 9.8).

## Description

In the Linux kernel, the following vulnerability has been resolved:

batman-adv: reject oversized global TT response buffers

batadv_tt_prepare_tvlv_global_data() builds the allocation length for a
global TT response in 16-bit temporaries. When a remote originator
advertises a large enough global TT, the TT payload length plus the VLAN
header offset can exceed 65535 and wrap before kmalloc().

The full-table response path still uses the original TT payload length when
it fills tt_change, so the wrapped allocation is too small and
batadv_tt_prepare_tvlv_global_data() writes past the end of the heap object
before the later packet-size check runs.

Fix this by rejecting TT responses whose TVLV value length cannot fit in
the 16-bit TVLV payload length field.

## Key facts

- **CVE ID:** CVE-2026-31659
- **Published:** 2026-04-24
- **CVSS severity:** CRITICAL
- **CVSS base score:** 9.8
- **CWE codes:** NVD-CWE-noinfo

## Affected products

- `linux:linux_kernel`

## Primary sources

- NIST NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31659

## Citation

> AI Analytics. CVE-2026-31659. Retrieved 2026-08-08 from https://api.ai-analytics.org/cve/CVE-2026-31659. Derived from NIST NVD. Licensed CC0.

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