SumatraPDFReader SumatraPDF up to 3.5.2 External Editor CreateProcessW input validation

Summaryinfo

A vulnerability classified as critical was found in SumatraPDFReader SumatraPDF up to 3.5.2. The affected element is the function CreateProcessW of the component External Editor. The manipulation results in input validation. This vulnerability is cataloged as CVE-2026-107734. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability classified as critical has been found in SumatraPDFReader SumatraPDF up to 3.5.2. Affected is the function CreateProcessW of the component External Editor. The manipulation with an unknown input leads to a input validation vulnerability. CWE is classifying the issue as CWE-20. The 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. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability is traded as CVE-2026-107734 since 10/08/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. Successful exploitation requires user interaction by the victim. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 10/09/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Vendor

• SumatraPDFReader

Name

• SumatraPDF

Version

• 3.5.0
• 3.5.1
• 3.5.2

Website

• Product: https://github.com/sumatrapdfreader/sumatrapdf/

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If you want to get best quality of vulnerability data, you may have to visit VulDB.

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