CVE-2026-74650: staging: rtl8723bs: fix OOB read in WMM_param_handler()

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

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

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

staging: rtl8723bs: fix OOB read in WMM_param_handler()

WMM_param_handler() copies a fixed-size WMM parameter element out of a
received information element without checking that the element is long
enough, causing an out-of-bounds read for a short WMM IE.

The handler reads sizeof(struct WMM_para_element) (18) bytes at
pIE->data + 6, so it requires pIE->length to be at least 24
(WLAN_WMM_LEN), but it never validates the length. Two of its three
callers reach it after matching only the WMM OUI: OnAssocRsp() in
rtw_mlme_ext.c matches a 6-byte OUI, and join_cmd_hdl() matches a
4-byte OUI, before calling the handler. A vendor-specific IE carrying
the WMM OUI but a length between 6 and 23, placed in an association
response or in the IE blob handed to join_cmd_hdl(), passes the OUI
check and then makes the memcmp() and memcpy() at pIE->data + 6 read
past the end of the element. OnAssocRsp() parses a frame received from
the AP, so this is reachable from a remote peer.

The remaining caller in rtw_wlan_util.c already guards the handler with
"pIE->length == WLAN_WMM_LEN". Move the equivalent check into the
handler itself so every caller is covered; the sibling IE handlers in
the same parsing loop (HT_caps_handler(), HT_info_handler(),
ERP_IE_handler()) likewise bound their accesses by pIE->length.

The Linux kernel CVE team has assigned CVE-2026-74650 to this issue.


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

	Issue introduced in 4.12 with commit 554c0a3abf216c991c5ebddcdb2c08689ecd290b and fixed in 5.15.216 with commit 6cdca4c8b64c15a3ab9ad7a85f482e9519eadf93
	Issue introduced in 4.12 with commit 554c0a3abf216c991c5ebddcdb2c08689ecd290b and fixed in 6.1.183 with commit 2bee6f7a0f0125238951e31da2e96d06fe359043
	Issue introduced in 4.12 with commit 554c0a3abf216c991c5ebddcdb2c08689ecd290b and fixed in 6.6.152 with commit 1158b9931207392d6dd136aa0c4be18893b50fa1
	Issue introduced in 4.12 with commit 554c0a3abf216c991c5ebddcdb2c08689ecd290b and fixed in 6.12.104 with commit ce2399717de242344880044b91a20a712644fdfb
	Issue introduced in 4.12 with commit 554c0a3abf216c991c5ebddcdb2c08689ecd290b and fixed in 6.18.45 with commit e5b7610008f4e6a80c8b071aa77ddbd5e17ea472
	Issue introduced in 4.12 with commit 554c0a3abf216c991c5ebddcdb2c08689ecd290b and fixed in 7.1.9 with commit e429c6dfd5d2324cd866daaf4c29d5cfe4dea0e4
	Issue introduced in 4.12 with commit 554c0a3abf216c991c5ebddcdb2c08689ecd290b and fixed in 7.2 with commit ae21407350151bddfd4fea7aa39bd0643c0ca9d3

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-2026-74650
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/staging/rtl8723bs/core/rtw_wlan_util.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/6cdca4c8b64c15a3ab9ad7a85f482e9519eadf93
	https://git.kernel.org/stable/c/2bee6f7a0f0125238951e31da2e96d06fe359043
	https://git.kernel.org/stable/c/1158b9931207392d6dd136aa0c4be18893b50fa1
	https://git.kernel.org/stable/c/ce2399717de242344880044b91a20a712644fdfb
	https://git.kernel.org/stable/c/e5b7610008f4e6a80c8b071aa77ddbd5e17ea472
	https://git.kernel.org/stable/c/e429c6dfd5d2324cd866daaf4c29d5cfe4dea0e4
	https://git.kernel.org/stable/c/ae21407350151bddfd4fea7aa39bd0643c0ca9d3