Buffer overflow in Ffmpeg
CVE-2026-125235
FFmpeg through 9.0.2 contains a heap overflow vulnerability in libavcodec/qsvenc.c that allows attackers to corrupt memory by reusing an undersized pooled QSVFrame buffer when input dimensions increase. Attackers can supply crafted input whose resolution grows mid-stream, transcoded with Intel Quick Sync encoders without rescaling, to crash the application or corrupt heap memory.
Vulnerability class: Buffer Overflow
Published .
CVSS v3 metric
CVSS v3 base score 7.0 (High). Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- code.ffmpeg.org/FFmpeg/FFmpeg/pulls/25682 (issue-tracking)
- github.com/FFmpeg/FFmpeg (product)
- github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/qsvenc.c (technical-description)
- github.com/FFmpeg/FFmpeg/commit/9b99973b2bbecee0b7e1e57035b95498b42f54a6 (patch)
- www.vulncheck.com/advisories/ffmpeg-through-9.0.2-heap-overflow-via-qsv-encoder… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-125235?
- CVE-2026-125235 is a high-severity vulnerability in Ffmpeg, classified under Heap-based Buffer Overflow. CVSS score: 7.0/10. Published 2026-11-09.
- How severe is CVE-2026-125235?
- High severity. CVSS v3 base score is 7.0 out of 10.