CVE-2026-75147: FFmpeg Out-of-Bounds Read in AV1 RTP Packetizer via rtpenc_av1.c
FFmpeg before commit 983dae9 contains an out-of-bounds read in the AV1 RTP packetizer (libavformat/rtpencav1.c). The keyframe detection loop that searches for a sequence header OBU advanced its pointer and remaining-size counter by the encoded header length plus the OBU payload size without first bounding the OBU size against the remaining data. A crafted OBU size causes the remaining-size counter to wrap to a positive value, causing the next loop iteration to dereference a pointer beyond the end of the packet buffer. A crafted AV1 input packet muxed to RTP triggers the out-of-bounds read.
Affected Software
Event History
Frequently Asked Questions
Which deployments are exposed to this issue?
Deployments that use FFmpeg to mux AV1 input packets into RTP are exposed. The vulnerable logic is in the AV1 RTP packetizer in libavformat/rtpenc_av1.c.
What is required to trigger the out-of-bounds read?
An attacker needs a crafted AV1 input packet with an OBU size that causes the packetizer's remaining-size counter to wrap. The packet must be processed while FFmpeg is muxing it to RTP.
How can I determine whether the issue is fixed in a source-based build?
The issue is fixed by commit 983dae9c19f46c87d597598c0fd2f2fcee0ad2f8. Builds that predate this commit are affected according to the available information.