What’s Vulnerable › Vulnerabilities

CVE-2026-65704: FFmpeg 8.1.2 Out-of-Bounds Write via TY Demuxer and Shorten Decoder

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-23 · updated 2026-08-07
• Weakness: CWE-191

Description

FFmpeg through 8.1.2 contains an out-of-bounds write vulnerability that allows attackers to cause heap corruption by supplying a crafted ffconcat file processed with the -safe 0 flag. The TY demuxer's demux_audio() function decrements packet size without bounds checking, producing a negative size value that is passed to memcpy() in shorten_decode_frame(), where conversion to size_t wraps the value to near SIZE_MAX and triggers reads beyond the source allocation and writes far beyond the Shorten decoder's bitstream buffer.

Affected products

• FFmpeg: through 8.1.2

References

• https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/de771bd52774a52d45b0e2c82e56995a1ef40df7
• https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/23767
• https://www.vulncheck.com/advisories/ffmpeg-out-of-bounds-write-via-ty-demuxer-and-shorten-decoder

Get alerted when CVE-2026-65704 or the next vulnerability affects your stack