CVE-2026-25920CWE-125

SumatraPDF has a heap out-of-bounds read in MOBI HuffDic decompressor

Medium · published February 9, 2026

CVSS v3.1
5.5
EPSS
0%
Percentile
17.2
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
5.5 · MEDIUM
Vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
CVSS v4.0
Not supplied
EPSS
0.00263 · 17.2th percentile
Weakness
CWE-125 · Out-of-bounds Read
Published
2026-02-09T21:32Z
EPSS history
Timeline
  • 09 FEB 21:32Z
    SumatraPDF has a heap out-of-bounds read in MOBI HuffDic decompressor
    cvelistv5