Integer overflow in Ffmpeg
CVE-2026-125267
FFmpeg before 8.1.3 and 9.x before 9.0.2 contains a heap out-of-bounds write vulnerability in the APAC decoder in libavcodec/apac.c caused by an unreset bitstream index. Attackers can supply a crafted APAC file whose growing bitstream_index triggers an integer overflow, bypassing the reallocation check so memcpy() corrupts heap memory or crashes the application.
Vulnerability class: Integer Overflow
Published .
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/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/24432 (issue-tracking)
- github.com/FFmpeg/FFmpeg/commit/e15ddb7f9a2f9b3ab8ac305efb6f94ddc18463d0 (patch)
- github.com/FFmpeg/FFmpeg/blob/n9.0.1/libavcodec/apac.c (technical-description)
- github.com/FFmpeg/FFmpeg (product)
- www.vulncheck.com/advisories/ffmpeg-before-8.1.3-and-9-x-before-9.0.2-heap-out-… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-125267?
- CVE-2026-125267 is a high-severity vulnerability in Ffmpeg, classified under Integer Overflow or Wraparound. CVSS score: 7.8/10. Published 2026-11-09.
- How severe is CVE-2026-125267?
- High severity. CVSS v3 base score is 7.8 out of 10.