CVE-2026-107737Medium· 5.7▾ TwilightPoC available

SumatraPDF is a multi-format reader for Windows

▾ Twilight zone — High severity, or a signal on a lesser flaw

Depth score43/ 100 · Moderate

impact 31.4 · likelihood 0 · exploitation 12

⚡ Agent-ready:Raw markdown ↗JSON ↗

Proof of concept

A public proof-of-concept already exists for this vulnerability — see Exploit availability below.

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Published

Oct 8, 2026

Updated

Oct 13, 2026

CVSS

5.7

Vendor

sumatrapdfreader

Product

sumatrapdf

CWE

CWE-129

Depth score

43 · Moderate

EPSS

0.18% · p8

Platforms

—

Source

NVD

Vector

CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CISA SSVC

decided 2026-10-13

Exploitation: poc
Automatable: no
Technical impact: partial

Stakeholder-Specific Vulnerability Categorization from CISA's ADP record at CVE.org: whether exploitation is observed, whether an attack can be automated, and how much of the system is at stake. The CVSS score shown above comes from the assigning CNA record, not NVD.

EPSS history

Exploit-prediction probability, daily snapshots since Oct 10.

0.1% → 0.2%▲ 0.06%

Timeline

Disclosure to exploitation, from the record and what we observed since indexing it.

7 events · 18 days

Oct 8, 2026Published
Disclosed via NVD
Oct 10, 2026EPSS first tracked
0.1%
Oct 13, 2026Record revised
Last analysed / modified upstream
Oct 15, 2026Public exploit observed
Exploit / PoC code exists
Oct 15, 2026CVSS changed
— → 5.7
Oct 15, 2026Severity changed
none → medium
Oct 26, 2026EPSS peak
0.1% → 0.2%

sumatrapdfreader CWE-129 #nvd #cve.org #exploit-available

Affected

sumatrapdf <= 3.6.1

Full technical detail▾

Overview

SumatraPDF is a multi-format reader for Windows. In 3.6.1 and earlier, and in pre-release 3.7.0.20369 when WebView2 is absent or cannot initialize, ParseProtoUrl() accepts the signed host component of an its:// URL and FindHtmlWindowById() uses it directly as an index into gHtmlWindows. Opening a crafted CHM through the IE fallback backend with a negative or otherwise out-of-range window identifier can cause an out-of-bounds pointer read followed by an invalid object callback dereference and process termination. No fixed version is available as of this review.

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

References

Change history

Field changes observed since this record was first indexed.

Oct 15, 2026Public exploit / PoC published
Oct 15, 2026CVSS — → 5.7
Oct 15, 2026Severity none → medium

Related vulnerabilities

Connected by shared product, vendor, weakness, or advisory.

#nvd#cve.org#exploit-available

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