CVE-2026-68472: wifi: cfg80211: validate EHT MLE before MLD ID read

From: Greg Kroah-Hartman <[email protected]>

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

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

wifi: cfg80211: validate EHT MLE before MLD ID read

cfg80211_gen_new_ie() copies ML probe response elements from
the parent frame when the parent EHT multi-link element has an
MLD ID matching the nontransmitted BSSID index.

The code only checked that the extension element had more than
one byte before calling ieee80211_mle_get_mld_id(). That helper
assumes a BASIC MLE with enough common info and documents that
callers must first use ieee80211_mle_type_ok().

Attack chain:
malicious AP sends a short EHT MLE in an MBSSID beacon.
cfg80211_inform_bss_frame_data() stores the copied IE buffer.
cfg80211_parse_mbssid_data() builds the nontransmitted BSS IE.
cfg80211_gen_new_ie() sees the EHT MLE in the parent frame.
ieee80211_mle_get_mld_id() then reads past the IE boundary.

Validate the MLE type and size before reading the MLD ID. This
matches the contract required by the MLE helper and rejects the
short element before any internal MLE fields are accessed.

The Linux kernel CVE team has assigned CVE-2026-68472 to this issue.


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

	Issue introduced in 6.14 with commit 61dcfa8c2a8f6c53ce77b2c832b82990754b2aa9 and fixed in 6.18.40 with commit 584657c5fc58d7a840623a2fa06331c9661dd0f1
	Issue introduced in 6.14 with commit 61dcfa8c2a8f6c53ce77b2c832b82990754b2aa9 and fixed in 7.1.5 with commit 3b0505e43da8fb5b2a7994c3c3604e5a74692154
	Issue introduced in 6.14 with commit 61dcfa8c2a8f6c53ce77b2c832b82990754b2aa9 and fixed in 7.2-rc4 with commit 74e27cd1d98b546fdb276008a83708d062339661

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-2026-68472
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:
	net/wireless/scan.c


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/584657c5fc58d7a840623a2fa06331c9661dd0f1
	https://git.kernel.org/stable/c/3b0505e43da8fb5b2a7994c3c3604e5a74692154
	https://git.kernel.org/stable/c/74e27cd1d98b546fdb276008a83708d062339661