CVE-2026-107734: sumatrapdfreader sumatrapdf Improper Input Validation

Vulnerability summary

CVE-2026-107734 is a high (CVSS 7.1) Improper Input Validation vulnerability in sumatrapdfreader sumatrapdf. EPSS estimates a 0.14% chance of exploitation in the next 30 days, higher than 3.1% of scored vulnerabilities.

Timeline

1. 08-10-2026
   PublishedVulnerability first disclosed.
2. 09-10-2026
   Last modifiedVulnerability information updated.

Description

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.

• CWE-20Improper Input ValidationThe product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
• CWE-88Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')The product constructs a string for a command to be executed by a separate component in another control sphere, but it does not properly delimit the intended arguments, options, or switches within that command string.