CVE-2026-26054 — SumatraPDF: Heap out-of-bounds read in MOBI header parser.
SumatraPDF is a multi-format reader for Windows. Prior to 3.6, the MobiDoc::ParseHeader function in src/MobiDoc.cpp validates a record using kMobiHeaderMinLen but DecodeMobiDocH…
Published: 2026-09-24 · CVSS: 6.8 · CVSS 4.0
SumatraPDF is a multi-format reader for Windows. Prior to 3.6, the MobiDoc::ParseHeader function in src/MobiDoc.cpp validates a record using kMobiHeaderMinLen but DecodeMobiDocHeader constructs a decoder sized for kMobiHeaderLen without receiving the actual remaining buffer length. A malformed MOBI file can use an attacker-controlled header length to bypass optional-field early returns and cause the decoder to read beyond a short heap buffer. Opening the crafted document can crash SumatraPDF. This issue is fixed in version 3.6.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7