← Vulnerability feed

Vulnerability record · CVE-2026-25920 · published 9 February 2026

CVE-2026-25920: Sumatrapdfreader sumatrapdf out-of-bounds read vulnerability

Sumatrapdfreader · Sumatrapdf

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.

5.5 CVSS 3.1 Medium EPSS 0.23% · top 87.6% CWE-125 · Out-of-bounds read
5.5CVSS 3.1 base score
0.23%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
3References, 1 tagged exploit
17 Jun 2026Last modified by NVD

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:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/sumatrapdfreader/sumatrapdf/blob/916392f94bc34e24f3c3286893ac6d7fa1e1c428/src/MobiDoc.cpp Product
https://github.com/sumatrapdfreader/sumatrapdf/commit/12b6887e9dfff874fe8749bab1bdc53d4ff075b3 Product
https://github.com/sumatrapdfreader/sumatrapdf/security/advisories/GHSA-5mwx-65x7-cffp ExploitVendor Advisory

Track CVE-2026-25920 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.3CVE-2012-4895Sumatrapdfreader sumatrapdf memory buffer overflow vulnerabilityHeap-based buffer overflow in SumatraPDF before 2.1 allows remote attackers to execute arbitrary code via a crafted PDF document, a different vulnera…EPSS 5.2%9.3CVE-2012-4896Sumatrapdfreader sumatrapdf memory buffer overflow vulnerabilityHeap-based buffer overflow in SumatraPDF before 2.1 allows remote attackers to execute arbitrary code via a crafted PDF document, a different vulnera…EPSS 5.2%9.3CVE-2009-4117Sumatrapdfreader sumatrapdf memory buffer overflow vulnerabilityMultiple stack-based buffer overflows in pdf_shade4.c in MuPDF before commit 20091125231942, as used in SumatraPDF before 1.0.1, allow remote attacke…EPSS 7.8%7.8CVE-2026-25880Sumatrapdfreader sumatrapdf untrusted search path vulnerabilitySumatraPDF 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 i…EPSS 0.20%7.8CVE-2026-23512Sumatrapdfreader sumatrapdf untrusted search path vulnerabilitySumatraPDF is a multi-format reader for Windows. In 3.5.2 and earlier, there is a Untrusted Search Path vulnerability when Advanced Options setting i…EPSS 0.22%7.8CVE-2012-5340Sumatrapdfreader sumatrapdf integer overflow vulnerabilitySumatraPDF 2.1.1/MuPDF 1.0 allows remote attackers to cause an Integer Overflow in the lex_number() function via a corrupt PDF file.EPSS 5.7%7.8CVE-2013-2830Sumatrapdfreader sumatrapdf use after free vulnerabilityUse-after-free vulnerability in SumatraPDF Reader 2.x before 2.2.1 allows remote attackers to execute arbitrary code via a crafted PDF file.EPSS 3.6%7.5CVE-2026-25961Sumatrapdfreader sumatrapdf improper certificate validation vulnerabilitySumatraPDF is a multi-format reader for Windows. In 3.5.0 through 3.5.2, SumatraPDF's update mechanism disables TLS hostname verification (INTERNET_F…EPSS 0.44%

Source: NIST National Vulnerability Database (record CVE-2026-25920), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.