Bug 2536146 (CVE-2026-90366)

Summary:	CVE-2026-90366 kernel: wifi: mt76: mt7996: reserve space for the CSA-abort countdown TLV
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	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
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the Linux kernel's mt76 Wi-Fi driver, specifically affecting mt7996 devices. When a Channel Switch Announcement (CSA) countdown is active and Multiple Basic Service Set Identifier (MBSSID) is enabled, the driver may attempt to write more beacon data than allocated. This can lead to a buffer overflow, triggering a kernel panic and resulting in a denial of service (DoS) to the system.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-09-17 16:40:47 UTC

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

wifi: mt76: mt7996: reserve space for the CSA-abort countdown TLV

When a CSA countdown is active, mt7996_mcu_beacon_cntdwn() emits two
bss_bcn_cntdwn_tlv entries (the CSA countdown and the CCA-abort BCC), but
MT7996_BEACON_UPDATE_SIZE only reserved one. With MBSSID enabled and a
near-maximum beacon template the extra 8 bytes could push the offload
command past MT7996_MAX_BSS_OFFLOAD_SIZE and trigger skb_over_panic().
Reserve room for both countdown TLVs.

Comment 1 gkamathe 2026-09-22 08:01:48 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90366.mbox