---
id: CVE-2026-64223
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  wifi: mac80211: consume only present negotiated TTLM maps

  ieee80211_tid_to_link_map_size_ok() validates negotiated TTLM elements
  against the number of link-map entries…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  wifi: mac80211: consume only present negotiated TTLM maps

  ieee80211_tid_to_link_map_size_ok() validates negotiated TTLM elements
  against the number of link-map entries…
severity: high
cvss: 8.1
cvssVector: 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H'
published: '2026-07-24'
updated: '2026-07-27'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-64223'
references:
  - url: 'https://git.kernel.org/stable/c/2becaaeebe230ade1fcd5d0f1cde4d6ee93ec78f'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/2dd9304727c7041df0a599595910bdbe02ad03c5'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a6e6ccd5bd07155c2add6c74ce1a5e68ad3b95ea'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/f7d395dc5008168ac5b9c1ac2791e59a6078cca1'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.00385
epssPercentile: 0.29793
ingestedAt: '2026-07-27T06:16:49.215Z'
---

## Overview

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

wifi: mac80211: consume only present negotiated TTLM maps

ieee80211_tid_to_link_map_size_ok() validates negotiated TTLM elements
against the number of link-map entries indicated by link_map_presence.
ieee80211_parse_neg_ttlm() must consume the same layout.

The parser advanced its cursor for every TID, including TIDs whose
presence bit is clear and therefore have no map bytes in the element.
A sparse map can then make a later present TID read past the validated
element.

The bad bytes land in neg_ttlm->{up,down}link[tid] but are gated by
valid_links before being applied to driver state, so a peer cannot
turn the read into a policy change.  Under KUnit + KASAN with an
exact-sized element allocation the OOB read is reported as a
slab-out-of-bounds; whether the same trigger fires under the
production RX path depends on surrounding allocator state.

Advance the cursor only when the current TID has a map present.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.