Memory disclosure via truncated Screenpresso frames
Published Aug 6, 2026 · Updated Aug 6, 2026
Uninitialized heap reads in FFmpeg 3.0 and later before 9.0 allow attackers to recover process memory through crafted SPV1 packets. The screenpresso_decode_frame() function accepts a zlib stream that produces less than a full frame, then copies full frame dimensions from unwritten portions of persistent ctx->inflated_buf. Exploitation requires FFmpeg or a libavcodec consumer to decode attacker-supplied Screenpresso media and expose the resulting frame; persistent services risk disclosure of prior heap contents.
Summary
What happened
Uninitialized heap reads in FFmpeg 3.0 and later before 9.0 allow attackers to recover process memory through crafted SPV1 packets. The screenpresso_decode_frame() function accepts a zlib stream that produces less than a full frame, then copies full frame dimensions from unwritten portions of persistent ctx->inflated_buf. Exploitation requires FFmpeg or a libavcodec consumer to decode attacker-supplied Screenpresso media and expose the resulting frame; persistent services risk disclosure of prior heap contents.
The record
- CVE
- CVE-2026-70630
- Published
- Aug 6, 2026
- Updated
- Aug 6, 2026
- Vendor
- FFmpeg
- Product
- FFmpeg
- Classifications
- CWE-908
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 6, 2026CVE publishedPublication date reported by the CVE source.
- Aug 6, 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?
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- Affected versionversion=3.0 <9.0
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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