Vulnerability Description
Mailpit is an email testing tool and API for developers. Versions 1.28.0 and below have a Server-Side Request Forgery (SSRF) vulnerability in the /proxy endpoint, allowing attackers to make requests to internal network resources. The /proxy endpoint validates http:// and https:// schemes, but it does not block internal IP addresses, enabling attackers to access internal services and APIs. This vulnerability is limited to HTTP GET requests with minimal headers. The issue is fixed in version 1.28.1.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Axllent | Mailpit | < 1.28.1 |
Related Weaknesses (CWE)
References
- https://github.com/axllent/mailpit/commit/3b9b470c093b3d20b7d751722c1c24f3eed2e1Patch
- https://github.com/axllent/mailpit/security/advisories/GHSA-8v65-47jx-7mfrExploitVendor Advisory
- https://github.com/axllent/mailpit/security/advisories/GHSA-8v65-47jx-7mfrExploitVendor Advisory
FAQ
What is CVE-2026-21859?
CVE-2026-21859 is a vulnerability with a CVSS score of 5.8 (MEDIUM). Mailpit is an email testing tool and API for developers. Versions 1.28.0 and below have a Server-Side Request Forgery (SSRF) vulnerability in the /proxy endpoint, allowing attackers to make requests t...
How severe is CVE-2026-21859?
CVE-2026-21859 has been rated MEDIUM with a CVSS base score of 5.8/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-21859?
Check the references section above for vendor advisories and patch information. Affected products include: Axllent Mailpit.