CVE-2025-55161: stirling pdf SSRF — Exploit & Fix

Description

Stirling-PDF is a locally hosted web application that performs various operations on PDF files. Prior to version 1.1.0, when using the /api/v1/convert/markdown/pdf endpoint to convert Markdown to PDF, the backend calls a third-party tool to process it and includes a sanitizer for security sanitization which can be bypassed and result in SSRF. This issue has been patched in version 1.1.0.

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CVSS v3.1 Score

8.6

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L

Weakness Type (CWE)

CWE-918 Server-Side Request Forgery (SSRF)

Affected Products

Vendor	Product	Versions
stirlingpdf	stirling_pdf	< 1.1.0

References

Advisories & Patches

https://github.com/Stirling-Tools/Stirling-PDF/commit/7d6b70871bad2a3ff810825f7382c49f55293943

Exploits

https://github.com/Stirling-Tools/Stirling-PDF/security/advisories/GHSA-ff33-grr6-rmvp

Frequently Asked Questions

What is CVE-2025-55161? +

Stirling-PDF is a locally hosted web application that performs various operations on PDF files. Prior to version 1.1.0, when using the /api/v1/convert/markdown/pdf endpoint to convert Markdown to PDF, the backend calls a third-party tool to process it and includes a sanitizer for security sanitization which can be bypassed and result in SSRF. This issue has been patched in version 1.1.0. It has a CVSS v3.1 base score of 8.6 (HIGH).

How severe is CVE-2025-55161? +

CVE-2025-55161 has a CVSS v3.1 score of 8.6 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2025-55161? +

CVE-2025-55161 affects products from stirlingpdf, specifically: stirling_pdf. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-55161? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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