CVE-2026-21859 MEDIUM

CVE-2026-21859: Mailpit Proxy Endpoint is Vulnerable to Server-Side Request Forgery (SSRF)

Vendor Axllent

Product mailpit

Weakness CWE-918 · SSRF

Published January 7, 2026

Last update January 8, 2026

View on NVD All CVEs

CVSS base score

5.8/10

Attack vector Network

Attack complexity Low

Privileges required None

User interaction None

Confidentiality Low

Integrity None

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

January 7, 2026 CVE published

January 8, 2026 Record updated

External resources

03References

NVD — National Vulnerability Database https://nvd.nist.gov/vuln/detail/CVE-2026-21859 CWE — Common Weakness Enumeration https://cwe.mitre.org/data/definitions/918.html

Related vulnerabilities

04Related CVE

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