Medium [CVE-2026-70630] Information disclosure via uninitialized heap memory read in Screenpresso decoder
This medium-severity Red Hat Linux advisory covers CVE-2026-70630.
Android app · Google Play
Monitor future Red Hat Linux CVEs from your phone.
Choose a whole vendor or a precise platform, then receive matching security advisories by phone notification, email, or both. Coverage follows 32 official vendor sources and 160+ reviewed platform categories.
Summary
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.
A flaw was found in FFmpeg. This occurs when a crafted SPV1 packet with a valid zlib stream is supplied, causing the screenpresso_decode_frame() function to fail in validating the produced byte count.
When decoding a crafted SPV1 packet containing a truncated zlib stream, screenpresso_decode_frame() fails to validate the decompressed byte length before invoking av_image_copy_plane(). When FFmpeg operates in persistent or shared-process services, processing untrusted media can expose sensitive memory contents, posing a Moderate impact to confidentiality.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · high-confidence parse· fetched 3 hours ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · high-confidence parse· fetched 3 hours ago·verify at source
Mitigation checklist
- Avoid decoding untrusted Screenpresso (SPV1) media files using FFmpeg in persistent services. If processing untrusted input is required, run FFmpeg inside an ephemeral container or restricted systemd sandbox to prevent sensitive cross-session heap data disclosure.
Official advisory · high-confidence parse· fetched 3 hours ago·verify at source
Discussion(0)
No comments yet. Share field notes, upgrade gotchas, or questions — verify against the vendor advisory before acting on community advice.
Sign in to join the discussion.