CVE-2026-21859: GO-2026-4284 - Mailpit Proxy Endpoint has Server-Side Request Forgery (SSRF) vulnerability in github.com/axllent/mailpit

CVE-2026-21859 · Severity: low · CVSS 3.1 · Published 2026-01-12

Mailpit Proxy Endpoint has Server-Side Request Forgery (SSRF) vulnerability in github.com/axllent/mailpit

Technologies: github.com/axllent/mailpit (Go). Vendors: Go.

Quick answers

Is CVE-2026-21859 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-21859 being exploited in the wild.
How severe is CVE-2026-21859?
Low severity, with a CVSS score of 3.1, published 12 January 2026.
Which products and versions are affected?
github.com/axllent/mailpit (Go) SEMVER:introduced=0,fixed=1.28.1.
Is there a fix for CVE-2026-21859?
Yes. github.com/axllent/mailpit (Go): upgrade to 1.28.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
Am I affected by CVE-2026-21859?
Check whether you run github.com/axllent/mailpit (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • github.com/axllent/mailpit (Go): upgrade to 1.28.1 or later
    go get github.com/axllent/mailpit@v1.28.1

Affected products

  • github.com/axllent/mailpit (Go) SEMVER:introduced=0,fixed=1.28.1

Identifiers

  • CVE-2026-21859
  • GHSA-8v65-47jx-7mfr
  • GO-2026-4284

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