FFmpeg before commit 983dae9 contains an out-of-bounds read in the AV1 RTP packetizer (libavformat/rtpenc_av1.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.
https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/24096
https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/983dae9c19f46c87d597598c0fd2f2fcee0ad2f8
Published: 2026-08-19
Updated: 2026-08-19
Base Score: 6.6
Vector: CVSS2#AV:L/AC:L/Au:N/C:C/I:N/A:C
Severity: Medium
Base Score: 7.1
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H
Severity: High
Base Score: 6.9
Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N
Severity: Medium