Vulnerability in Ffmpeg
CVE-2026-125175
FFmpeg through 9.0.2 contains an information disclosure vulnerability in flashsv_decode_block() in libavcodec/flashsv.c that copies uninitialized heap memory into decoded frames when inflate output is short. Attackers can supply a crafted FLV with an FSV1 stream whose zlib block data decompresses short, then recover heap contents from the decoded or re-encoded output.
Published .
CVSS v3 metric
CVSS v3 base score 3.3 (Low). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N.
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/24464 (issue-tracking)
- github.com/FFmpeg/FFmpeg (product)
- github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/flashsv.c (technical-description)
- github.com/FFmpeg/FFmpeg/commit/50d206a75b5e60261d71b25657ae04891eb60290 (patch)
- github.com/FFmpeg/FFmpeg/commit/cfb40c912927fdd2c1186b7b6aca468422da23db (patch)
- www.vulncheck.com/advisories/ffmpeg-through-9.0.2-information-disclosure-via-fl… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-125175?
- CVE-2026-125175 is a low-severity vulnerability in Ffmpeg, classified under Use of Uninitialized Resource. CVSS score: 3.3/10. Published 2026-11-09.
- How severe is CVE-2026-125175?
- Low severity. CVSS v3 base score is 3.3 out of 10.