Heap Buffer Over-read in libheif HEIF and AVIF File Decoder from Struktur AG

CVE-2025-68431

What is CVE-2025-68431?

The libheif library, used for HEIF and AVIF file format decoding, is susceptible to a heap buffer over-read due to a flaw in the handling of overlay image items. Specifically, prior to version 1.21.0, the 'HeifPixelImage::overlay()' method could process a crafted HEIF image which results in a negative row length calculation. This error, likely caused by an invalid or unclipped overlay rectangle, leads to an underflow when converted to 'size_t' for memory operations. As a result, the library attempts to read beyond the allocated memory, which can lead to crashes and unpredictable behavior during image decoding. To resolve this issue, users should upgrade to at least version 1.21.0 or avoid using images with 'iovl' overlay boxes as a temporary workaround.

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