CVE-2026-23845 (GCVE-0-2026-23845)
Vulnerability from cvelistv5 – Published: 2026-01-19 19:01 – Updated: 2026-01-20 20:05
VLAI
EPSS
VEX
Title
Mailpit Vulnerable to Server-Side Request Forgery (SSRF) via HTML Check API
Summary
Mailpit is an email testing tool and API for developers. Versions prior to 1.28.3 are vulnerable to Server-Side Request Forgery (SSRF) via HTML Check CSS Download. The HTML Check feature (`/api/v1/message/{ID}/html-check`) is designed to analyze HTML emails for compatibility. During this process, the `inlineRemoteCSS()` function automatically downloads CSS files from external `<link rel="stylesheet" href="...">` tags to inline them for testing. Version 1.28.3 fixes the issue.
Severity
5.8 (Medium)
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-01-20 20:04 UTC
CWE
- CWE-918 - Server-Side Request Forgery (SSRF)
Assigner
GitHub_M
CNA
References
3 references
| URL | Tags |
|---|---|
| https://github.com/axllent/mailpit/security/advis… | x_refsource_CONFIRM |
| https://github.com/axllent/mailpit/commit/1679a0a… | x_refsource_MISC |
| https://github.com/axllent/mailpit/releases/tag/v1.28.3 | x_refsource_MISC |
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Nomenclature
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The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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