CVE-2026-68402

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

wifi: cfg80211: bound element ID read when checking non-inheritance

cfg80211_is_element_inherited() reads the first data octet of the candidate element (id = elem->data[0]) to look it up in an extension non-inheritance list. It does so after testing elem->id, but without verifying that the element actually has a data octet. A zero-length extension element (WLAN_EID_EXTENSION with length 0) therefore makes it read one octet past the end of the element.

_ieee802_11_parse_elems_full() runs this check for every element of a frame once a non-inheritance context exists – e.g. while parsing a per-STA profile of a Multi-Link element in a (re)association response, or a non-transmitted BSS profile – so a crafted frame from an AP can trigger a one-octet slab-out-of-bounds read during element parsing:

BUG: KASAN: slab-out-of-bounds in cfg80211_is_element_inherited Read of size 1 … in net/wireless/scan.c

Return early (treat the element as inherited) when an extension element carries no data, mirroring the existing handling of empty ID lists.

The bug was found by fuzzing ieee802_11_parse_elems_full() under KASAN.

Weakness

The product reads data past the end, or before the beginning, of the intended buffer.

Affected Software

Potential Mitigations

• Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
• When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
• Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
• To reduce the likelihood of introducing an out-of-bounds read, ensure that you validate and ensure correct calculations for any length argument, buffer size calculation, or offset. Be especially careful of relying on a sentinel (i.e. special character such as NUL) in untrusted inputs.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/540.html

References

• https://git.kernel.org/stable/c/11ac7a5e75f5132f1778e0c60981d30dc29fb869
• https://git.kernel.org/stable/c/20c308d9a57722801961f816395bf825f7bde6bc
• https://git.kernel.org/stable/c/24154c172246ae3f0e69bb17c9111095685ceedc
• https://git.kernel.org/stable/c/2d31ebb26a14f103c9cdc5287fb20cb2d4bde901
• https://git.kernel.org/stable/c/521dd5fe6d12b0d3c275f919738dc3a07117f4a5
• https://git.kernel.org/stable/c/84bd907361c56fbd5523eceb2682cb39da059bd5
• https://git.kernel.org/stable/c/cb8afea4655ff004fa7feee825d5c79783525383
• https://git.kernel.org/stable/c/ddf2773bcc8e49a43c561f22ec1e7924215d7947