FFmpeg 7.0 before 8.1.3 and 9.x before 9.0.2 contains a heap out‑of‑bounds write flaw in vk_av1_decode_slice(). The flaw occurs because the tile‑count limit is validated only at function entry. An adversary can craft an AV1 bitstream with more than 256 tiles and feed it through the Vulkan hardware accelerator, forcing the decoder to write beyond the bounds of tile_sizes and corrupt heap memory. This memory corruption can lead to a crash or other instability.

Vendors: FFmpeg. Product: FFmpeg. Vulnerable releases include any build from 7.0 up to but not including 8.1.3, and any 9.x release up to but not including 9.0.2. Any system that uses these versions of FFmpeg with the Vulkan hardware accelerator enabled is susceptible. No newer branches or minor releases are listed as affected.

The CVSS score of 7.3 signals a high impact severity, while the EPSS score is not reported and KEV does not list this vulnerability, indicating no current evidence of exploitation. The vulnerability requires only that a malicious AV1 stream be decoded via Vulkan, making the attack vector likely local or remote if the application processes untrusted media. The resulting heap corruption could cause a crash or denial of service. Because the vulnerability can be triggered by normal media processing, the potential risk is significant for any user or application that accepts external AV1 content on an affected system.