Integer overflow in Ffmpeg
CVE-2026-96611
FFmpeg before 9.0 has a signed integer overflow in libavformat/mov.c. In mov_read_ispe(), uint32_t width/height values from a crafted HEIF ispe box are stored into signed int fields without bounds checking, allowing values exceeding INT_MAX to become negative. In read_image_grid(), accumulating these values causes signed integer overflow (undefined behavior per C17 section 6.5), which on x86 wraps to a small positive value, bypassing downstream validity checks.
Vulnerability class: Integer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.9 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L.
EPSS exploit prediction
EPSS: 0.001 (1.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 1st percentile — 1.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: -0.000
Affected products
Weakness classification (CWE)
References
- code.ffmpeg.org/FFmpeg/FFmpeg/pulls/23455 (Patch, Issue Tracking)
- code.ffmpeg.org/FFmpeg/FFmpeg/commit/059eb2e853c1f62b8df1b73be9318061a7a21b0b (Patch)
Frequently asked questions
- What is CVE-2026-96611?
- CVE-2026-96611 is a medium-severity vulnerability in Ffmpeg, classified under Integer Overflow or Wraparound. CVSS score: 6.9/10. Published 2026-09-23.
- How severe is CVE-2026-96611?
- Medium severity. CVSS v3 base score is 6.9 out of 10.