CVE-2026-55586
Gravedad CVSS v3.1:
MEDIA
Tipo:
CWE-119
Restricción de operaciones inapropiada dentro de los límites del búfer de la memoria
Fecha de publicación:
20/08/2026
Última modificación:
20/08/2026
Descripción
*** Pendiente de traducción *** SumatraPDF is a multi-format reader for Windows. In 3.6.1 and earlier, a crafted CHM file can supply malformed LZX Huffman code lengths to make_decode_table in ext/CHMLib/lzx.c. In the long-code branch, the function writes new internal nodes through next_symbol before validating that the canonical Huffman table has overflowed. The PRETREE case can write beyond the 104-entry PRETREE_table into adjacent heap state in struct LZXstate when reached through chm_open, chm_retrieve_object, LZXdecompress, and BUILD_TABLE. This produces heap memory corruption in the parser process, while arbitrary code execution has not been demonstrated. No fixed version is available as of this review.
Impacto
Puntuación base 3.x
6.60
Gravedad 3.x
MEDIA