Mailpit
CVE-2026-27808
MEDIUM
GHSA-mpf7-p9x7-96r3
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V4 - API and Web Service URL allowlisting, SSRF prevention
MITRE ATT&CK
2 techniques across 2 tactics: Initial Access, Credential Access The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS 5.8 (MEDIUM). Attack vector: Network. Complexity: Low. Privileges required: None. User interaction: None. Exploitation no authentication required. Exploitable via remote/network. Public exploit/POC available. |
| Exploit ScenarioDerived | A remote attacker without authentication could exploit this vulnerability to compromise the affected system. |
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Alert meAnalysisAIv1 – Mar 12, 2026
Mailpit versions prior to 1.29.2 contain a Server-Side Request Forgery vulnerability in the Link Check API that allows unauthenticated remote attackers to perform HTTP requests to arbitrary hosts, including internal and private IP addresses. The API fails to validate or filter target URLs and returns status codes for each link, enabling non-blind SSRF attacks. Public exploit code exists for this vulnerability, affecting deployments with default configuration.
Earlier versions of this analysis (1)
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). [CVSS 5.8 MEDIUM]
RemediationAI
A vendor patch is available — apply it immediately. Restrict network access to the affected service where possible.
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in go
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
Classified as CWE-918 (Server-Side Request Forgery (SSRF)). Affects Mailpit. 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 ful
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Severity by source
AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N
Primary rating from GitHub Advisory.
CVSS VectorGitHub Advisory
Lifecycle Timeline
3DescriptionGitHub Advisory
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.
Executive ViewAI
Organizations using Mailpit should be aware of moderate risk from CVE-2026-27808, a server-side request forgery vulnerability rated CVSS 5.8. Users could be tricked into performing unintended actions. Proof-of-concept code is publicly available. A patch is available and should be applied during regular vulnerability management.
Apply vendor patch. If patching is delayed: implement egress filtering, block metadata endpoints.
Threat Intelligence Overview
NVD
CVE.org
EPSS
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Server-Side Request Forgery exploits applications that fetch remote resources based on user-supplied URLs.
Affected Products (CPE)GitHub Advisory
Mailpit versions up to 1.28.2 contains a vulnerability that allows attackers to intercept sensitive data such as email c
Mailpit versions 1.28.0 and earlier contain a server-side request forgery vulnerability in the /proxy endpoint that perm
Mailpit versions before 1.28.3 contain a server-side request forgery vulnerability in the HTML Check feature that allows
Header injection in Mailpit's SMTP server prior to version 1.28.3 allows unauthenticated remote attackers to inject or m
Cross-site WebSocket hijacking in Mailpit 1.29.0-1.30.5 exposes live email metadata to any website the developer visits,
Memory exhaustion in Mailpit's SMTP server (versions 1.30.0 through 1.30.4) allows unauthenticated remote SMTP clients t
Exploit-DB