Buffer overflow in Ffmpeg
CVE-2026-30754
A memory corruption vulnerability exists in FFmpeg before 8.1. The RTP encoding process. In the nal_send function in libavformat/rtpenc_h264_hevc.c, a negative size parameter (size=-3) is passed to memcpy when transmitting H.264/HEVC streams via RTP using a crafted input file. This was detected using AddressSanitizer.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.005 (43.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 44th percentile — 43.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: +0.000
Affected products
Weakness classification (CWE)
References
- code.ffmpeg.org/FFmpeg/FFmpeg/pulls/20746 (Patch, Issue Tracking)
- github.com/momo-trip/poc_ffmpeg (Exploit)
- gist.github.com/momo-trip/4cddf2c9e15600873de55259dac6b0e6 (Third Party Advisory)
Frequently asked questions
- What is CVE-2026-30754?
- CVE-2026-30754 is a high-severity vulnerability in Ffmpeg, classified under Out-of-bounds Write. CVSS score: 8.8/10. Published 2026-09-08.
- How severe is CVE-2026-30754?
- High severity. CVSS v3 base score is 8.8 out of 10.