Bug 2506807 (CVE-2026-64223)

Summary: CVE-2026-64223 kernel: wifi: mac80211: consume only present negotiated TTLM maps
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's mac80211 Wi-Fi driver. This vulnerability, an out-of-bounds read, occurs when parsing negotiated Time-To-Live Map (TTLM) elements. A remote attacker could craft a sparse map, causing the parser to read beyond the intended memory boundary. While direct policy changes are prevented, this issue can lead to memory corruption, potentially impacting system stability.
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Description OSIDB Bzimport 2026-07-24 16:04:47 UTC
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.

Comment 1 Mauro Matteo Cascella 2026-07-28 11:30:35 UTC
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026072417-CVE-2026-64223-b945@gregkh/T