CVE-2026-27808

The record

Mailpit is an email testing tool and API for developers. Prior to version 1.29.2, the Link Check API (/api/v1/message/{ID}/link-check) is vulnerable to Server-Side Request Forgery (SSRF). The server performs HTTP HEAD requests to every URL found in an email without validating target hosts or filtering private/internal IP addresses. The response returns status codes and status text per link, making this a non-blind SSRF. In the default configuration (no authentication on SMTP or API), this is fully exploitable remotely with zero user interaction. This is the same class of vulnerability that was fixed in the HTML Check API (CVE-2026-23845 / GHSA-6jxm-fv7w-rw5j) and the screenshot proxy (CVE-2026-21859 / GHSA-8v65-47jx-7mfr), but the Link Check code path was not included in either fix. Version 1.29.2 fixes this vulnerability.

Affected packages

Related vulnerabilities

• GHSA-mpf7-p9x7-96r3 Mailpit is Vulnerable to Server-Side Request Forgery (SSRF) via Link Check API Same vulnerability
• GO-2026-4333 Mailpit has an SMTP Header Injection via Regex Bypass in github.com/axllent/mailpit Also affects github.com/axllent/mailpit
• GO-2026-4345 Mailpit has a Server-Side Request Forgery (SSRF) via HTML Check API in… Also affects github.com/axllent/mailpit
• GO-2026-4310 Mailpit is vulnerable to Cross-Site WebSocket Hijacking (CSWSH) allowing unauthenticated… Also affects github.com/axllent/mailpit
• CVE-2026-23845 Mailpit is an email testing tool and API for developers. Also affects github.com/axllent/mailpit
• CVE-2026-23829 Mailpit is an email testing tool and API for developers. Also affects github.com/axllent/mailpit
• GO-2026-4284 Mailpit Proxy Endpoint has Server-Side Request Forgery (SSRF) vulnerability in… Also affects github.com/axllent/mailpit
• CVE-2026-22689 Mailpit is an email testing tool and API for developers. Also affects github.com/axllent/mailpit