FFmpeg versions from 3.0 up to, but not including, 9.0 contain an uninitialized heap memory read vulnerability in the native Screenpresso decoder… (CVE-2026-70630)
FFmpeg versions from 3.0 up to, but not including, 9.0 contain an uninitialized heap memory read vulnerability in the native Screenpresso decoder (libavcodec/screenpresso.c) that allows attackers to recover sensitive memory contents by supplying a crafted SPV1 packet with a valid zlib stream that decompresses fewer bytes than the full frame requires. The screenpresso_decode_frame() function fails to validate the produced byte count before calling av_image_copy_plane() to copy the complete frame dimensions from the persistent ctx->inflated_buf buffer, causing unwritten heap memory from prior allocations or prior frames to be copied into decoded output and potentially exposing sensitive data such as userspace addresses from persistent decoding services.
AI Analysis
Technical Summary
The vulnerability (CVE-2026-70630) exists in FFmpeg's native Screenpresso decoder (libavcodec/screenpresso.c) in versions >=3.0 and <9.0. An attacker can craft an SPV1 packet with a valid zlib stream that decompresses fewer bytes than expected. The screenpresso_decode_frame() function does not verify the decompressed byte count before calling av_image_copy_plane(), which copies the full frame size from a persistent buffer. This results in copying uninitialized heap memory from prior allocations or frames into the decoded output, potentially leaking sensitive information such as userspace memory addresses from persistent decoding services.
Potential Impact
An attacker with the ability to supply crafted SPV1 packets can cause the decoder to leak uninitialized heap memory contents. This may expose sensitive information, including userspace addresses, which could aid in further attacks. There is no indication of integrity or availability impact. The vulnerability requires local access (AV:L) and user interaction (UI:R).
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or patch links are provided in the available data. Users should monitor vendor advisories for updates and avoid processing untrusted SPV1 packets with affected FFmpeg versions.
FFmpeg versions from 3.0 up to, but not including, 9.0 contain an uninitialized heap memory read vulnerability in the native Screenpresso decoder… (CVE-2026-70630)
Description
FFmpeg versions from 3.0 up to, but not including, 9.0 contain an uninitialized heap memory read vulnerability in the native Screenpresso decoder (libavcodec/screenpresso.c) that allows attackers to recover sensitive memory contents by supplying a crafted SPV1 packet with a valid zlib stream that decompresses fewer bytes than the full frame requires. The screenpresso_decode_frame() function fails to validate the produced byte count before calling av_image_copy_plane() to copy the complete frame dimensions from the persistent ctx->inflated_buf buffer, causing unwritten heap memory from prior allocations or prior frames to be copied into decoded output and potentially exposing sensitive data such as userspace addresses from persistent decoding services.
CVSS v3.1
Score 5.5medium
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability (CVE-2026-70630) exists in FFmpeg's native Screenpresso decoder (libavcodec/screenpresso.c) in versions >=3.0 and <9.0. An attacker can craft an SPV1 packet with a valid zlib stream that decompresses fewer bytes than expected. The screenpresso_decode_frame() function does not verify the decompressed byte count before calling av_image_copy_plane(), which copies the full frame size from a persistent buffer. This results in copying uninitialized heap memory from prior allocations or frames into the decoded output, potentially leaking sensitive information such as userspace memory addresses from persistent decoding services.
Potential Impact
An attacker with the ability to supply crafted SPV1 packets can cause the decoder to leak uninitialized heap memory contents. This may expose sensitive information, including userspace addresses, which could aid in further attacks. There is no indication of integrity or availability impact. The vulnerability requires local access (AV:L) and user interaction (UI:R).
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or patch links are provided in the available data. Users should monitor vendor advisories for updates and avoid processing untrusted SPV1 packets with affected FFmpeg versions.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-7mrq-j773-6867
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-70630"]
- Ecosystems
- []
- Database Specific Severity
- MODERATE
- Cvss Version
- 3.1
Threat ID: 6a75739bbf8831d539d91c2e
Added to database: 08/07/2026, 05:56:43 UTC
Last enriched: 08/07/2026, 09:00:23 UTC
Last updated: 08/08/2026, 00:41:15 UTC
Views: 2
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