Description

FFmpeg versions 8.0 through 8.1.2 contains a stack buffer overflow vulnerability in the Vulkan HEVC hardware decoder that allows remote attackers to overwrite return addresses and adjacent stack frames by supplying a crafted HEVC/H.265 bitstream. Attackers can embed a malicious vps_num_hrd_parameters value exceeding HEVC_MAX_SUB_LAYERS in any supported container format to overflow stack-allocated arrays in the vk_hevc_end_frame function, potentially achieving arbitrary code execution.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "8.8",
  "pubDate": "2026-07-22T17:16:58.697Z",
  "pubdate": "2026-07-22T17:16:58.697Z",
  "executiveSummary": "FFmpeg versions 8.0 through 8.1.2 contain a critical stack buffer overflow vulnerability within the Vulkan HEVC hardware decoder. This security flaw allows remote attackers to overwrite return addresses and adjacent stack frames by supplying a maliciously crafted HEVC or H.265 bitstream embedded within any supported container format. Successful exploitation of this vulnerability can lead to memory corruption, potentially achieving arbitrary code execution within the context of the running application. The vulnerability poses significant risk to systems processing untrusted video streams, as it requires no prior authentication or elevated privileges from the attacker. Exploitation relies entirely on the ingestion and decoding of the malformed multimedia input containing the oversized parameter values.",
  "technicalDetails": "The vulnerability resides in the vk_hevc_end_frame function of the FFmpeg Vulkan HEVC hardware decoder component. The root cause is an insufficient bounds check on the vps_num_hrd_parameters value parsed from the HEVC/H.265 bitstream. Specifically, an attacker can supply a malicious vps_num_hrd_parameters value that exceeds the predefined constant HEVC_MAX_SUB_LAYERS. When the decoding routine processes this malformed input, it writes data into stack-allocated arrays within the vk_hevc_end_frame function without adequately validating the size of the incoming data against the destination buffer allocation limits. This condition results in a classic stack buffer overflow. The attack flow begins when a remote attacker distributes a crafted HEVC/H.265 bitstream encapsulated in any container format supported by FFmpeg, such as MP4, MKV, or TS. When an affected application or media player processes the malicious file, the FFmpeg library parses the invalid header fields. The out-of-bounds write operation subsequently corrupts adjacent stack frames, overwriting saved frame pointers and return addresses. When the vulnerable function attempts to return execution control, the instruction pointer is redirected to attacker-controlled memory locations if a precise payload is engineered. This enables potential arbitrary code execution with the privileges of the user running the media processing application. The vulnerability affects FFmpeg versions 8.0 through 8.1.2, operates without requiring authentication or privileges, and can be triggered locally via file processing or remotely via network streams depending on the application architecture."
}