OpenSlide is a C library for reading whole slide image files. From 3.4.1 until 4.0.1, OpenSlide's parselevel0xml() processing in src/openslide-vendor-ventana.c accepts nonpositive row or column tile counts from a crafted Ventana BIF file. The invalid counts produce attacker-controlled relative memory offsets and allow arbitrary values to be written at those offsets, affecting all supported platforms and configurations and resulting in a crash or potential arbitrary code execution. This issue is fixed in version 4.0.1.

OpenSlide is a C library for reading whole slide image files. Prior to 4.0.1, a behavior change in libtiff 4.7.1 causes the indirect TIFF tile path in src/openslide-decode-tiff.c and openslidetiffreadtile() to request a full-height destination for a partial bottom tile row, allowing uninitialized heap memory to enter pixel data returned by openslidereadregion(). A crafted but valid slide can trigger the issue in TIFF-based formats other than Hamamatsu NDPI when a network service renders attacker-provided slides. Successful extraction depends on pixel transparency handling and recompression, OpenSlide with libtiff 4.7.0 or earlier is not affected, and official binary builds 4.0.0.10 and 4.0.0.11 are affected. This issue is fixed in OpenSlide 4.0.1 and official binary build 4.0.0.12.