1. Home
  2. CVE Database
  3. CVE-2026-25920
MEDIUM · 5.5

CVE-2026-25920

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 ...

Vulnerability Description

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.

CVSS Score

5.5

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH

Affected Products

VendorProductVersions
SumatrapdfreaderSumatrapdf<= 3.5.2

Related Weaknesses (CWE)

CWE-125

References

FAQ

What is CVE-2026-25920?

CVE-2026-25920 is a vulnerability with a CVSS score of 5.5 (MEDIUM). 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 ...

How severe is CVE-2026-25920?

CVE-2026-25920 has been rated MEDIUM with a CVSS base score of 5.5/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-25920?

Check the references section above for vendor advisories and patch information. Affected products include: Sumatrapdfreader Sumatrapdf.