CVE-2026-74649

Technical Description

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

staging: rtl8723bs: fix missing shared-key auth challenge length check

The WEP shared-key authentication handler uses the challenge-text

element's attacker-controlled length without checking it against the

fixed 128-byte chg_txt buffer.

In OnAuthClient() the length from rtw_get_ie() - up to 255 - is used

to perform memcpy() into the 128-byte pmlmeinfo->chg_txt, so a

malicious AP sending a malformed WLAN_EID_CHALLENGE element can

overflow/underfill chg_txt by up to 127 bytes. It is reachable over the

air, before association, during shared-key authentication. In the case

of an overflow, the driver can write out of bounds. In the case of an

underfill, the driver can echo stale buffer memory.

The challenge text is defined to be exactly 128 octets, which is

already provided as the WLAN_AUTH_CHALLENGE_LEN define; require the

element to be exactly that length before use.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References