CVE-2026-43110

A flaw was found in the Linux kernel's brcmfmac Wi-Fi driver. This vulnerability occurs because the driver fails to properly validate bsscfg indices in interface (IF) events. An attacker could exploit this by sending a specially crafted IF event with an invalid bsscfg index, which could lead to an out-of-bounds write or read, potentially causing a system crash and resulting in a denial of service (DoS).

brcmfmac IF event handling validates the firmware provided ifidx but still uses the raw bsscfgidx value as an index into the driver iflist array. A malformed firmware IF event with an out of range bsscfgidx can cause an out of bounds pointer read and may lead to an invalid pointer dereference or broader memory corruption depending on how the resulting ifp is used. For the CVSS the PR:N is used in the paranoid score because a practical attacker model may involve adjacent Wi-Fi influence over FullMAC firmware events rather than a local privileged user on the host. The issue is not reachable over a normal routed IP network. It is adjacent network or device firmware mediated. Impact is at least denial of service through a kernel crash or Wi-Fi driver failure. In the paranoid case, the unchecked firmware controlled array index potentially could lead to possible confidentiality and integrity impact (but primarily only Availability impact).

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

To mitigate this issue, prevent module brcmfmac from being loaded. Please see https://access.redhat.com/solutions/41278 for how to blacklist a kernel module to prevent it from loading automatically.