CVE-2026-55586

SumatraPDF 3.6.1 and earlier (Windows) contains a heap out-of-bounds write in the vendored CHMLib LZX decompressor. A crafted CHM file can supply malformed Huffman code lengths to make_decode_table in ext/CHMLib/lzx.c. In the long-code branch, internal nodes are written via next_symbol before val...