Heap corruption via TY packet-size underflow
Published Jul 23, 2026 · Updated Jul 23, 2026
Out-of-bounds write in FFmpeg 8.1.2 and earlier allows attackers to corrupt heap memory via a crafted ffconcat file. The TY demuxer's demux_audio() decrements packet size below zero and passes it to Shorten's memcpy(), where size_t conversion creates a near-SIZE_MAX copy. Processing must use the -safe 0 flag; the malformed file can read beyond its source allocation and overwrite the decoder's bitstream buffer.
Summary
What happened
Out-of-bounds write in FFmpeg 8.1.2 and earlier allows attackers to corrupt heap memory via a crafted ffconcat file. The TY demuxer's demux_audio() decrements packet size below zero and passes it to Shorten's memcpy(), where size_t conversion creates a near-SIZE_MAX copy. Processing must use the -safe 0 flag; the malformed file can read beyond its source allocation and overwrite the decoder's bitstream buffer.
The record
- CVE
- CVE-2026-65704
- Published
- Jul 23, 2026
- Updated
- Jul 23, 2026
- Vendor
- FFmpeg
- Product
- FFmpeg
- Classifications
- CWE-787, CWE-191, T1203
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 23, 2026CVE publishedPublication date reported by the CVE source.
- Jul 23, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <=8.1.2
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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