Bug 2536459 (CVE-2026-90349)

Summary: CVE-2026-90349 kernel: wifi: mt76: mt7996: fix out-of-bounds link array access in mt7996_tx()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's mt76 wireless driver, specifically within the `mt7996_tx()` function. When the `mac80211` subsystem leaves the link unspecified, the driver substitutes a primary link ID that is then used without proper bounds checking to access internal arrays. This unchecked access can lead to an out-of-bounds memory read or write, potentially causing system instability or a denial of service (DoS).
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-09-17 18:01:47 UTC 
In the Linux kernel, the following vulnerability has been resolved:

wifi: mt76: mt7996: fix out-of-bounds link array access in mt7996_tx()

When mac80211 leaves the link unspecified, mt7996_tx() substitutes the
primary link id of the station or vif. That value is
IEEE80211_LINK_UNSPECIFIED (0xf) until the first link has been added,
and it is then used unchecked to index vif->link_conf[],
mvif->mt76.link[] and sta->link[], all of which hold
IEEE80211_MLD_MAX_NUM_LINKS (15) entries.

Clamp the primary link id to the default link before using it, and use
the clamped value for the link_sta fallback as well.
Comment 1 gkamathe 2026-09-22 06:06:07 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90349.mbox