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    CVE-2026-25961

    SumatraPDF is a multi-format reader for Windows. In 3.5.0 through 3.5.2, SumatraPDF's update mechanism disables TLS hostname verification (INTERNET_FLAG_IGNORE_CERT_CN_INVALID) and executes installers without signature checks. A network attacker with any valid TLS certificate (e.g., Let's Encrypt) can intercept the update check request, inject a malicious installer URL, and achieve arbitrary code execution.

    Published:Feb 9, 2026
    Last Modified:Apr 17, 2026
    EPS:Feb 9, 2026
    EPSS Score:0.00022
    CVSS Score:7.5

    Affected Products

    Vendor
    Sumatrapdfreader
    Product
    Sumatrapdf

    Exploits

    https://github.com/sumatrapdfreader/sumatrapdf/security/advisories/GHSA-xpm2-rr5m-x96qhttps://www.exploit-db.com/exploits/52535https://github.com/mbanyamer/CVE-2026-25961-SumatraPDF-3.5.0---3.5.2-RCE

    Related CVEs

    CVE-2026-55586 (CVSS 6.6) — SumatraPDF is a multi-format reader for Windows. In 3.6.1 and earlier, a crafted CHM file can supply malformed…
    CVE-2026-25920 (CVSS 5.5) — SumatraPDF is a multi-format reader for Windows. In 3.5.2 and earlier, a heap out-of-bounds read vulnerability…
    CVE-2026-25880 (CVSS 7.8) — SumatraPDF is a multi-format reader for Windows. In 3.5.2 and earlier, the PDF reader allows execution of a ma…
    CVE-2026-23951 (CVSS 5.5) — SumatraPDF is a multi-format reader for Windows. All versions contain an off-by-one error in the validation co…
    CVE-2026-23512 (CVSS 8.6) — SumatraPDF is a multi-format reader for Windows. In 3.5.2 and earlier, there is a Untrusted Search Path vulner…
    CVE-2025-57248 (CVSS 7.3) — A null pointer dereference vulnerability was discovered in SumatraPDF 3.5.2 during the processing of a crafted…
    CVE-2023-33802 (CVSS 5.5) — A buffer overflow in SumatraPDF Reader v3.4.6 allows attackers to cause a Denial of Service (DoS) via a crafte…
    CVE-2012-5340 (CVSS 7.8) — SumatraPDF 2.1.1/MuPDF 1.0 allows remote attackers to cause an Integer Overflow in the lex_number() function v…
    CVE-2013-2830 (CVSS 7.8) — Use-after-free vulnerability in SumatraPDF Reader 2.x before 2.2.1 allows remote attackers to execute arbitrar…
    CVE-2012-4895 (CVSS 9.3) — Heap-based buffer overflow in SumatraPDF before 2.1 allows remote attackers to execute arbitrary code via a cr…

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High