A buffer overflow in the TH1520 AON firmware protocol driver can cause the kernel to write out of bounds when accessing the 'mode' field through an unsafe pointer arithmetic offset. This flaw classifies as a buffer overflow (CWE‑787, CWE‑823) and could allow a local attacker to corrupt kernel memory, potentially gaining arbitrary code execution or escalating privileges. The fix replaces unsafe pointer usage with safe calculations and swaps custom endianness macros for the kernel’s portable conversion functions, improving reliability and security. The vulnerability was identified by the Smatch static checker and has already been patched in the upstream kernel.

The flaw affects all Linux kernel builds that include the TH1520 driver before the patch. No specific release version is listed, but any kernel incorporating the original firmware protocol path in the kernel source subtree is implicated. Updates to the firmware driver and the kernel itself are required to remediate the issue.

The CVSS score of 7.8 indicates high severity, but the EPSS score is less than 1%, and the vulnerability is not listed in the CISA KEV catalog, indicating no known active exploit. The likely attack vector is local, requiring interaction with the kernel driver (e.g., loading firmware), and the vulnerability would need an attacker to trigger the specific buffer overflow condition. With these constraints, the overall risk remains high but the exploitation probability is very low.