Bug 2502460 (CVE-2026-64030)

Summary: CVE-2026-64030 kernel: wifi: mac80211: bounds-check link_id in ieee80211_ml_epcs
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: high    
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 Wi-Fi (mac80211) component. A connected WiFi 7 Access Point (AP) can trigger an out-of-bounds write by sending a specially crafted EPCS Enable Response action frame. This vulnerability can lead to a kernel crash, resulting in a Denial of Service (DoS) for the affected system.
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Description OSIDB Bzimport 2026-07-19 16:09:21 UTC
In the Linux kernel, the following vulnerability has been resolved:

wifi: mac80211: bounds-check link_id in ieee80211_ml_epcs

IEEE80211_MLE_STA_EPCS_CONTROL_LINK_ID is 0x000f, so link_id extracted
from a PRIO_ACCESS ML element PER_STA_PROFILE subelement can be 0..15.
sdata->link[] has IEEE80211_MLD_MAX_NUM_LINKS (15) entries (indices 0..14),
making index 15 out-of-bounds.

A connected WiFi 7 AP can trigger this by sending an EPCS Enable Response
action frame with a PER_STA_PROFILE subelement where link_id = 15.  The
unsolicited-notification path (dialog_token = 0) is reachable any time
EPCS is already enabled, without any prior client request.

sdata->link[15] reads into the first word of sdata->activate_links_work
(a wiphy_work whose embedded list_head is non-NULL after INIT_LIST_HEAD),
so the NULL check on the result does not catch the invalid access.  The
garbage pointer is then passed to ieee80211_sta_wmm_params(), which
dereferences link->sdata and crashes the kernel.

The same class of bug was fixed for ieee80211_ml_reconfiguration() by
commit 162d331d833d ("wifi: mac80211: bounds-check link_id in
ieee80211_ml_reconfiguration").

Comment 1 Mauro Matteo Cascella 2026-07-21 11:31:16 UTC
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026071903-CVE-2026-64030-51b6@gregkh/T