FFmpeg 8.1.2 OOB Write via crafted ffconcat (-safe 0) TY demuxer
CVE-2026-65704 Published on July 23, 2026
FFmpeg 8.1.2 Out-of-Bounds Write via TY Demuxer and Shorten Decoder
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.
Vulnerability Analysis
CVE-2026-65704 is exploitable with local system access. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity and availability.
Weakness Types
What is a Memory Corruption Vulnerability?
The software writes data past the end, or before the beginning, of the intended buffer. Typically, this can result in corruption of data, a crash, or code execution. The software may modify an index or perform pointer arithmetic that references a memory location that is outside of the boundaries of the buffer. A subsequent write operation then produces undefined or unexpected results.
CVE-2026-65704 has been classified to as a Memory Corruption vulnerability or weakness.
What is an Integer underflow Vulnerability?
The product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result. This can happen in signed and unsigned cases.
CVE-2026-65704 has been classified to as an Integer underflow vulnerability or weakness.
Products Associated with CVE-2026-65704
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Affected Versions
FFmpeg:- Before and including 8.1.2 is affected.
- Version de771bd52774a52d45b0e2c82e56995a1ef40df7 is unaffected.