Medium [CVE-2026-70631] Information disclosure via uninitialized heap memory read in TIFF decoder
This medium-severity Red Hat Linux advisory covers CVE-2026-70631 affecting Red Hat Enterprise Linux AI (RHEL AI) 3, Red Hat OpenShift AI (RHOAI).
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Summary
FFmpeg versions from 0.5 up to, but not including, 9.0 contain an uninitialized heap memory disclosure vulnerability in the native TIFF decoder in libavcodec/tiff.c.
An attacker who can cause FFmpeg to decode a crafted TIFF file can supply a valid Deflate-compressed strip that terminates successfully after producing fewer bytes than the declared strip requires.
The tiff_unpack_zlib() function allocates a heap buffer sized for the full declared strip but copies all declared rows via memcpy() regardless of how many bytes zlib actually decompressed, causing unwritten bytes that can contain stale data from prior heap allocations to be incorporated into decoded image output and potentially exposing sensitive data in persistent services.
A flaw was found in FFmpeg. An attacker can exploit an uninitialized heap memory disclosure vulnerability in the native TIFF decoder by providing a specially crafted TIFF file.
When decoding a crafted TIFF file containing an undersized Deflate-compressed strip, tiff_unpack_zlib() fails to verify actual decompressed output length before executing frame-buffer memcpy() operations. This incorporates uninitialized stale heap memory from prior allocations into the rendered image stream.
Affected products named by the advisory: Red Hat Enterprise Linux AI (RHEL AI) 3; Red Hat OpenShift AI (RHOAI).
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 processing untrusted TIFF files using FFmpeg in persistent or shared-process services. If processing untrusted media is required, isolate FFmpeg execution within an ephemeral container or tightly restricted systemd/SELinux sandbox to prevent cross-session memory disclosure.
Official advisory · high-confidence parse· fetched 3 hours ago·verify at source
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