CVE-2026-98186 in Linux
Summary
by MITRE • 10/06/2026
In the Linux kernel, the following vulnerability has been resolved:
wifi: mwifiex: bound the pairwise-cipher OUI walk to the IE length
mwifiex_search_oui_in_ie() reads a pairwise-cipher (PTK) count from a beacon/probe-response RSN or WPA information element and then walks that many 4-byte OUIs, comparing each with memcmp(). The count comes straight from the (attacker-supplied) IE and is never checked against the element's own length, and the callers admit the element on element_id alone (has_ieee_hdr() / has_vendor_hdr(), no length check). A crafted RSN/WPA IE with a large pairwise count therefore makes the walk read up to 255 * 4 bytes past the element -- an out-of-bounds read of the kmemdup()'d beacon buffer, reachable from any AP whose beacon/probe response is processed during scan-result parsing.
Pass the number of IE bytes available at the OUI list and bound the walk to the element. Keep the length signed and reject a negative value before any unsigned arithmetic, so a small or zero IE length cannot underflow to a large size_t and defeat the bound.
Found by 0sec automated security-research tooling (https://0sec.ai).
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Analysis
by VulDB Data Team • 10/07/2026
The vulnerability identified in the Linux kernel's mwifiex wireless driver represents a critical out-of-bounds read condition arising from insufficient validation of input data within Information Element processing logic. Specifically, the function mwifiex_search_oui_in_ie is responsible for parsing pairwise-cipher information elements found in beacon and probe-response frames transmitted by access points. The core technical flaw lies in the failure to validate the length field associated with these elements against the actual count of OUIs specified within them. When processing an RSN or WPA element, the driver extracts a pairwise cipher count directly from the attacker-supplied frame data without verifying that this count is consistent with the declared size of the information element itself. This lack of boundary checking allows for a scenario where a crafted Information Element declares a significantly larger number of OUIs than can physically fit within its allocated length field, leading to memory safety violations during subsequent processing steps.
From an operational perspective, this vulnerability enables remote attackers to trigger out-of-bounds reads by sending specially constructed beacon or probe-response frames containing malformed RSN or WPA elements. During the scan-result parsing phase, when the kernel processes these frames from any nearby access point, the mwifiex driver attempts to walk through a list of four-byte OUIs based on the unvalidated count. Because there is no check against the element's total length, the memory read operation can extend up to 255 times four bytes beyond the bounds of the kmemdup'd beacon buffer. This results in reading arbitrary kernel memory contents into user-space or internal structures depending on how the data is subsequently used. Such an out-of-bounds read constitutes a significant confidentiality risk as it may expose sensitive kernel data, potentially aiding further exploitation attempts such as information disclosure attacks that leverage leaked pointers or cryptographic keys stored in adjacent memory regions.
The root cause of this issue aligns with CWE-125, which describes Out-of-Bounds Read vulnerabilities where software reads data past the end, or before the beginning, of a buffer. In this specific instance, the failure to enforce length constraints on variable-length fields within network protocol structures is compounded by weak input validation at higher-level parsing functions like has_ieee_hdr and has_vendor_hdr, which accept elements based solely on their identifier without verifying structural integrity. This pattern reflects common pitfalls in handling binary protocols where trust assumptions about packet structure are not rigorously enforced before arithmetic operations involving buffer sizes are performed. The vulnerability is particularly dangerous because it can be triggered remotely by any wireless device within range that broadcasts the crafted frames, requiring no authentication or prior interaction with the target system beyond being within radio range during a scan operation.
To mitigate this risk, developers have implemented strict bounds checking on the OUI walk logic to ensure that the number of iterations does not exceed the available bytes in the Information Element. A critical aspect of this fix involves maintaining signed integer types for length calculations and explicitly rejecting negative values before any unsigned arithmetic is performed. This prevents underflow conditions where a small or zero element length could be interpreted as a large positive value due to type conversion, thereby defeating boundary checks. By ensuring that the walk remains strictly within the allocated buffer limits, the kernel eliminates the possibility of reading unauthorized memory regions. Systems running affected versions of the Linux kernel should apply the latest security patches provided by their distribution vendors to address this flaw and restore secure handling of wireless management frames.
This vulnerability is categorized under ATT&CK technique T1083, which covers File and Directory Discovery, as out-of-bounds reads can be used to enumerate system information in certain contexts, although its primary impact here is confidentiality leakage rather than direct file access. The discovery was facilitated by automated security research tooling from 0sec.ai, highlighting the importance of fuzzing and static analysis techniques in identifying subtle logic errors in low-level kernel drivers that handle complex protocol parsing. Continuous integration of rigorous input validation checks for all external data sources remains essential to prevent similar vulnerabilities in network-facing components of operating systems.