CVE-2026-96611: Ffmpeg

Medium severity, CVSS 6.9. EPSS: 0.1% chance of exploitation in the next 30 days.

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.

Affected products

• Ffmpeg Ffmpeg: before 9.0 (fixed in 9.0)

Published 2026-09-23. Last modified 2026-09-26.