CVE-2026-107734: Sumatrapdfreader Sumatrapdf

High severity, CVSS 7.1. EPSS: 0.1% chance of exploitation in the next 30 days.

SumatraPDF is a multi-format reader for Windows. In 3.5.2 and earlier, an attacker-controlled SyncTeX source filename is substituted for the %f placeholder in an external editor command line without safe Windows argument quoting, and the resulting command line is passed to CreateProcessW(). A user with an external editor configured or auto-detected who opens a PDF with a crafted .synctex.gz file and invokes inverse search can inject command-line flags; the resulting impact depends on the target editor interpreting those flags and can include unintended editor actions or code execution through a malicious extension. No broader impact is claimed beyond the advisory-supported conditions. No fixed version is available as of this review.

Affected products

• Sumatrapdfreader Sumatrapdf: up to and including 3.5.2

Published 2026-10-08. Last modified 2026-10-09.