CVE-2026-55586 (GCVE-0-2026-55586)
Vulnerability from cvelistv5
Published
2026-08-20 16:35
Modified
2026-08-21 21:47
CWE
  • CWE-119 - Improper Restriction of Operations within the Bounds of a Memory Buffer
  • CWE-787 - Out-of-bounds Write
Summary
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.
Impacted products
Vendor Product Version
sumatrapdfreader sumatrapdf Version: <= 3.6.1rel
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Show details on NVD website


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  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
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