CVE-2026-112394

Affected versions of the Pillow package are vulnerable to Buffer Over-read due to a mismatch between the bounds check used by the raw decoder and the actual memory footprint required by the bit-plane unpackers. `ImagingRawDecode` computes the per-line byte count as `(xsize * bits + 7) / 8` and uses this value both to validate the input buffer size and to advance between lines, whereas the `unpackP2L` and `unpackP4L` unpackers treat `P;2L` and `P;4L` data as 2 or 4 separate bit planes, each independently padded to a whole byte via `s = (pixels + 7) / 8`, making their true required size larger than what the decoder accounts for in certain width values such as 1. An attacker can exploit this by supplying a crafted buffer to `Image.frombytes()` or `Image.frombuffer()` with the `P;2L` or `P;4L` raw mode and a susceptible width/height, causing the unpackers to read 1 to 3 bytes past the end of the allocated buffer, which can leak adjacent heap memory into decoded pixel data or crash the process if the overread reaches unmapped memory.