Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:LSummary
CVE-2025-55161 is a high-severity SSRF (CWE-918) vulnerability in Stirlingpdf Stirling Pdf. Its CVSS base score is 8.6 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 21% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to AC-4 (Information Flow Enforcement) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
Stirling-PDF is a locally hosted web application for performing operations on PDF files. Prior to version 1.1.0, the /api/v1/convert/markdown/pdf endpoint invokes a third-party tool to convert Markdown input to PDF and applies a security sanitizer that can be bypassed, resulting in server-side request forgery (SSRF) classified under CWE-918. The flaw affects unauthenticated network requests to this endpoint and carries a CVSS 3.1 score of 8.6.
An attacker with network access can submit specially crafted Markdown payloads to the conversion endpoint, bypassing the sanitizer to force the application into making arbitrary requests to internal or external resources. This enables high-impact confidentiality exposure along with limited integrity and availability effects without requiring user interaction or credentials.
The project has released version 1.1.0 to address the issue, with the fix documented in commit 7d6b70871bad2a3ff810825f7382c49f55293943 and the GitHub Security Advisory GHSA-ff33-grr6-rmvp. The associated EPSS score remains at 0.0836 with no material increase from its peak value.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-24184
Vulnerability Data
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…
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sanitizer for security sanitization which can be bypassed and result in SSRF. This issue has been patched in version 1.1.0.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V1.3.6V1.5.3V5.3.2V10.4.7
Mitigating Controls (NIST 800-53 r5) AI
Information flow enforcement can restrict which destinations the server is allowed to contact on behalf of users.
Input validation directly stops untrusted URLs from being accepted and fetched without destination checks.
Boundary protection limits the network reach of server-initiated requests even if SSRF occurs.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure development practices directly include input validation and destination allow-listing that prevent SSRF.
Runtime monitoring of web applications and services can detect anomalous outbound requests indicative of SSRF.
Vulnerability identification processes can discover and record SSRF flaws in web applications.
Network segmentation and egress controls can limit the damage from successful SSRF requests.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Operational threat data describing SSRF campaigns can be used to tighten outbound-request allow-lists and detection rules before attackers exploit them.