CVE-2023-54284: 
Linux Kernel vulnerability analysis and mitigation

CVE-2023-54284 is a vulnerability in the Linux kernel's media: av7110 driver where an integer underflow can occur in the write_ts_to_decoder() function. The issue arises because a user-controlled value (buf[4], sourced via ts_play()) is used in a length calculation — len - (buf[4] + 1) - 4 — without validating that the result is non-negative. The vulnerability affects Linux kernel versions from 2.6.31 up to multiple stable branches, with fixes backported to versions 4.14.315, 4.19.283, 5.4.243, 5.10.211, 5.15.111, 6.1.28, 6.2.15, 6.3.2, and 6.4. It was published on December 30, 2025, and carries an estimated CVSS severity of Medium (Feedly, ENISA EUVD).

The root cause is an integer underflow (CWE-191) in the write_ts_to_decoder() function within the Linux kernel's av7110 DVB media driver. The buf[4] byte, which is a user-supplied u8 value passed through ts_play(), is used without bounds checking in the expression len - (buf[4] + 1) - 4 before being forwarded to av7110_ipack_instant_repack(). If buf[4] is sufficiently large, the computed length becomes negative (as a signed integer), potentially causing undefined behavior in downstream processing. The fix adds an explicit check to ensure the computed length is non-negative before proceeding, and removes the now-redundant if (!len) guard (Feedly).

The practical impact of this vulnerability is limited, as the av7110 driver targets legacy DVB hardware (AV7110-based satellite receiver cards) and exploitation requires local access to a system with this hardware and driver loaded. Passing a negative length to av7110_ipack_instant_repack() could result in unexpected kernel behavior, though the severity of any resulting memory corruption or stability issue is not clearly established. The vulnerability does not appear to enable remote code execution or privilege escalation under typical conditions (Feedly).

The Linux kernel maintainers have released patches across multiple stable branches. Users should update to the following fixed versions or later: 4.14.315, 4.19.283, 5.4.243, 5.10.211, 5.15.111, 6.1.28, 6.2.15, 6.3.2, or 6.4. As a workaround, systems that do not use AV7110-based DVB hardware can blacklist or unload the av7110 kernel module to eliminate the attack surface. Applying the relevant distribution vendor's kernel update is the recommended remediation (Feedly, ENISA EUVD).