CVE-2026-21859: Mailpit Proxy Endpoint has Server-Side Request Forgery (SSRF) vulnerability

January 6, 2026 (updated February 2, 2026)

A Server-Side Request Forgery (SSRF) vulnerability exists in Mailpit’s /proxy endpoint that allows attackers to make requests to internal network resources.

References

github.com/advisories/GHSA-8v65-47jx-7mfr
github.com/axllent/mailpit
github.com/axllent/mailpit/commit/3b9b470c093b3d20b7d751722c1c24f3eed2e19d
github.com/axllent/mailpit/security/advisories/GHSA-8v65-47jx-7mfr
nvd.nist.gov/vuln/detail/CVE-2026-21859
pkg.go.dev/vuln/GO-2026-4284

Code Behaviors & Features

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