CVE-2025-38343: 
Linux Kernel vulnerability analysis and mitigation

CVE-2025-38343 is a vulnerability in the Linux kernel's mt76 WiFi driver (mt7996 chipset) related to improper IEEE 802.11 fragmentation handling. The driver failed to drop Wi-Fi fragments with multicast or broadcast Receiver Address (RA), violating the IEEE 802.11 standard which mandates that fragmentation applies only to unicast frames. This issue mirrors the class of vulnerabilities described in CVE-2020-26145. Affected kernel versions include 6.2–6.6.94, 6.7–6.12.34, and 6.13–6.15.3. It was disclosed on July 10, 2025, with a CVSS v3.1 base score of 5.5 (Medium) (Red Hat Advisory, Red Hat Bugzilla).

The root cause is improper input validation in the mt7996 driver's fragment processing path (CWE-20), where the driver does not enforce the IEEE 802.11 requirement that fragmented frames must only be addressed to unicast destinations. An attacker with local access could craft or inject Wi-Fi frames with multicast or broadcast RA that are incorrectly processed as fragments, potentially causing unexpected driver behavior or denial of service. The fix, backported to stable kernel branches, adds an explicit check to drop any fragment whose RA is a multicast or broadcast address (Red Hat Bugzilla, Kernel Patch).

Successful exploitation could allow a local attacker to cause denial of service or disrupt Wi-Fi network communications on systems using the mt7996 chipset. The vulnerability has no confidentiality or integrity impact; the primary risk is availability degradation through network instability or unexpected driver behavior. The scope is limited to the local system and does not provide a path for remote code execution or lateral movement (Red Hat Advisory).

There is no public proof-of-concept exploit and no evidence of in-the-wild exploitation as of the time of disclosure. The vulnerability requires local access to the affected system, limiting its attack surface. The EPSS score is approximately 0.018% (0.000180), indicating a very low probability of exploitation in the near term. CVE-2025-38343 is not listed in the CISA Known Exploited Vulnerabilities catalog (Red Hat Advisory).

Update to a patched Linux kernel version: 6.6.95 or later (for the 6.2–6.6.x branch), 6.12.35 or later (for the 6.7–6.12.x branch), or 6.15.4 or later (for the 6.13–6.15.x branch). Ubuntu has issued security notices USN-7833-1 through USN-7833-4 addressing this vulnerability. As a workaround where patching is not immediately possible, restrict local user access to systems with mt7996-based Wi-Fi hardware and monitor for unusual Wi-Fi fragmentation traffic. Network segmentation can further reduce the potential attack surface (Red Hat Advisory, Ubuntu USN-7833-1).

Red Hat tracked the issue via Bugzilla (Bug 2379260) and assigned it to their Product Security DevOps Team. Ubuntu issued multiple security notices (USN-7833-1 through USN-7833-4) covering this CVE across various kernel flavors including Azure and GCP variants. No notable independent researcher commentary or significant social media discussion has been observed beyond standard vulnerability tracking (Red Hat Bugzilla, Ubuntu USN-7833-1).