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 makedecodetable in ext/CHMLib/lzx.c. In the long-code branch, the function writes new internal nodes through nextsymbol before validating that the canonical Huffman table has overflowed. The PRETREE case can write beyond the 104-entry PRETREEtable into adjacent heap state in struct LZXstate when reached through chmopen, chmretrieveobject, LZXdecompress, and BUILDTABLE. 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.

SumatraPDF is a multi-format reader for Windows. In 3.5.2 and earlier, a heap out-of-bounds read vulnerability exists in SumatraPDF's MOBI HuffDic decompressor. The bounds check in AddCdicData() only validates half the range that DecodeOne() actually accesses. Opening a crafted .mobi file can read nearly (1 << codeLength) bytes beyond the CDIC dictionary buffer, leading to a crash.

SumatraPDF is a multi-format reader for Windows. In 3.5.2 and earlier, the PDF reader allows execution of a malicious binary (explorer.exe) located in the same directory as the opened PDF when the user clicks File → “Show in folder”. This behavior leads to arbitrary code execution on the victim’s system with the privileges of the current user, without any warning or user interaction beyond the menu click.

SumatraPDF is a multi-format reader for Windows. All versions contain an off-by-one error in the validation code that only triggers with exactly 2 records, causing an integer underflow in the size calculation. This bug exists in PalmDbReader::GetRecord when opening a crafted Mobi file, resulting in an out-of-bounds heap read that crashes the app. There are no published fixes at the time of publication.

SumatraPDF is a multi-format reader for Windows. In 3.5.2 and earlier, there is a Untrusted Search Path vulnerability when Advanced Options setting is trigger. The application executes notepad.exe without specifying an absolute path when using the Advanced Options setting. On Windows, this allows execution of a malicious notepad.exe placed in the application's installation directory, leading to arbitrary code execution.