CVE-2026-65704

FFmpeg 8.1.2 Out-of-Bounds Write via TY Demuxer and Shorten Decoder

HIGH
7.8
CVSS Score
Published: July 23, 2026 at 06:55 PM UTC
Updated: August 7, 2026 at 12:30 AM UTC
1 product affected across 1 vendorFFMPEG

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Severity
HIGH7.8
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v ≤ 8.1.2
Vendor states this is fixed in de771bd52774a52d45b0e2c82e56995a1ef40df7 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.8HIGHVulnCheck
Attack Vector
LOCAL
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-787CWE-191

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