CVE-2026-90366: wifi: mt76: mt7996: reserve space for the CSA-abort countdown TLV

CVE-2026-90366: wifi: mt76: mt7996: reserve space for the CSA-abort countdown TLV

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

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.

The Linux kernel CVE team has assigned CVE-2026-90366 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.2 with commit 98686cd21624c75a043e96812beadddf4f6f48e5 and fixed in 6.6.157 with commit 1d348f96623ec20d700af7d4dfc00a74da6238ac
	Issue introduced in 6.2 with commit 98686cd21624c75a043e96812beadddf4f6f48e5 and fixed in 6.12.110 with commit bc1d694a1ffe0062c3adf0db1d64ad54454398ec
	Issue introduced in 6.2 with commit 98686cd21624c75a043e96812beadddf4f6f48e5 and fixed in 6.18.52 with commit 45d8896e4cffffb2c6554ccbec6efe7a0d53166f
	Issue introduced in 6.2 with commit 98686cd21624c75a043e96812beadddf4f6f48e5 and fixed in 7.2.6 with commit 1a51aff0e048dc5b8252d65808b79939c942d6ec
	Issue introduced in 6.2 with commit 98686cd21624c75a043e96812beadddf4f6f48e5 and fixed in 7.3-rc1 with commit 50c66bab321140c49aa2ed779a3ec9d2f085b458

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-90366
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/net/wireless/mediatek/mt76/mt7996/mcu.h


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/1d348f96623ec20d700af7d4dfc00a74da6238ac
	https://git.kernel.org/stable/c/bc1d694a1ffe0062c3adf0db1d64ad54454398ec
	https://git.kernel.org/stable/c/45d8896e4cffffb2c6554ccbec6efe7a0d53166f
	https://git.kernel.org/stable/c/1a51aff0e048dc5b8252d65808b79939c942d6ec
	https://git.kernel.org/stable/c/50c66bab321140c49aa2ed779a3ec9d2f085b458