UBUNTU-CVE-2026-125256: Buffer Overflow
FFmpeg through 9.0.2 contains a heap buffer overflow vulnerability in ffllvidencdiffbytesrvv() that allows attackers to corrupt heap memory by triggering negative length values in the Huffyuv encoder. Attackers can supply RGB video narrower than 8 or 16 pixels for huffyuv transcoding on RVV-enabled RISC-V builds, causing writes past the encoder's temp buffer.
Affected Software
Event History
Frequently Asked Questions
Which systems are exposed to this issue?
The issue affects FFmpeg through 9.0.2 when Huffyuv transcoding is performed on an RVV-enabled RISC-V build. The triggering input is RGB video with a width narrower than 8 or 16 pixels.
What must an attacker be able to do to exploit it?
An attacker must be able to cause Huffyuv transcoding of a crafted narrow RGB video on an affected RVV-enabled RISC-V FFmpeg build. The vulnerability is triggered by negative length values that cause writes beyond the encoder temporary buffer.
What is the impact of successful exploitation?
Successful exploitation can corrupt heap memory through a heap buffer overflow in ff_llvidenc_diff_bytes_rvv().
What can be done if patching is not immediately possible?
Avoid Huffyuv transcoding of RGB video narrower than 8 or 16 pixels on RVV-enabled RISC-V builds. Reject, resize, or otherwise prevent processing of such inputs until an update is applied.