CVE-2026-70630

Received Received - Intake

Heap Memory Leak in FFmpeg Screenpresso Decoder

Publication date: 2026-08-06

Last updated on: 2026-08-06

Assigner: VulnCheck

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 Scores

EPSS Scores

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Meta Information

Published

2026-08-06

Last Modified

2026-08-06

Generated

2026-08-07

AI Q&A

2026-08-07

EPSS Evaluated

N/A

NVD

CVE-2026-70630

Affected Vendors & Products

Vendor	Product	Version / Range
ffmpeg	ffmpeg	From 3.0 (inc) to 9.0 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-908	The product uses or accesses a resource that has not been initialized.

Attack-Flow Graph

Executive Summary

This vulnerability affects FFmpeg versions 3.0 to 9.0. It involves an uninitialized heap memory read in the Screenpresso decoder. Attackers can exploit it by sending a crafted SPV1 packet with a valid zlib stream that decompresses fewer bytes than needed. The decoder fails to check the produced byte count before copying data, exposing sensitive memory contents like userspace addresses from prior frames or allocations.

Impact Analysis

An attacker could exploit this to recover sensitive memory contents, potentially exposing userspace addresses or other confidential data processed by FFmpeg. This may lead to further attacks like privilege escalation or information disclosure if combined with other vulnerabilities.

Compliance Impact

This vulnerability could lead to unauthorized access to sensitive data, violating GDPR's data protection principles or HIPAA's confidentiality requirements. Organizations using vulnerable FFmpeg versions may face compliance breaches if sensitive data is exposed.

Mitigation Strategies

Upgrade FFmpeg to version 9.0 or later to address the uninitialized heap memory read vulnerability in the Screenpresso decoder. Ensure all systems using FFmpeg are updated to prevent potential sensitive memory exposure.

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