reject undecodable bmp bit depths in ParseHeader#421
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ermig1979 merged 1 commit intoJun 13, 2026
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Heap overflow on undecodable BMP bit depths
For any depth other than 8 or 24
ParseHeadersetschannelsto 4, so a 16-bit BMP (accepted by both the BITFIELDS and the uncompressed paths) ends up with_size = _width * 4while the bit-field masks it parses are never applied and no converter exists for it.FromStreamthen copies_width * 4bytes per row into a destination sized for the requested Gray8/Bgr24 output and runs past the image allocation, so rejecting the depths the loader cannot actually decode inParseHeaderlooks like the least invasive place to stop it. Proper 16-bit handling could be added later as a separate change.