CVE-2026-23845

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.

Affected Software

VendorProductVersion RangeStatus
axllentmailpit< 1.28.3affected

Weaknesses

  • CWE-918: CWE-918: Server-Side Request Forgery (SSRF)

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: yes
    • Technical Impact: partial

References