Medium (5.5) in sumatrapdfreader sumatrapdf. EPSS 0.3% chance of exploitation in the next 30 days.
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.
Severity
CVSS 3.1
5.5 medium
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
EPSS
0.3% chance of exploitation in the next 30 days; higher than 17% of CVEs (scores of 2026-10-31)