strukturag vulnerabilities and threats

CVE-2026-3949 is a medium-severity vulnerability in strukturag libheif versions up to 1.21.2, specifically in the HEIF file parser component's vvdec_push_data2 function. It allows a local attacker with limited privileges to trigger an out-of-bounds read by manipulating the size argument, potentially leading to information disclosure or application instability. Exploitation requires local access and no user interaction is needed. Although the exploit has been publicly disclosed, no known active exploitation in the wild has been reported. A patch identified by commit b97c8b5f198b27f375127cd597a35f2113544d03 addresses this issue. Organizations using libheif in media processing or image handling should apply the patch promptly to mitigate risks.

libheif is an HEIF and AVIF file format decoder and encoder. Prior to version 1.21.0, a crafted HEIF that exercises the overlay image item path triggers a heap buffer over-read in `HeifPixelImage::overlay()`. The function computes a negative row length (likely from an unclipped overlay rectangle or invalid offsets), which then underflows when converted to `size_t` and is passed to `memcpy`, causing a very large read past the end of the source plane and a crash. Version 1.21.0 contains a patch. As a workaround, avoid decoding images using `iovl` overlay boxes.