Description
Mailpit is an email testing tool and API for developers. Prior to 1.30.2, the remediation shipped for CVE-2026-27808 is incomplete because the tools.IsInternalIP deny-list in internal/tools/net.go relies on Go's standard library classification helpers and does not block IPv6 transition mechanisms or prefixes such as NAT64, 6to4, IPv4-compatible IPv6, ISATAP, fec0::/10, and 2001:db8::/32. An attacker who can deliver email and invoke POST /api/v1/message/{ID}/link-check can coerce the Link Check API's safeDialContext path into dialing internal destinations and can use status-code and error feedback to map internal service reachability, including cloud metadata endpoints. This issue is fixed in version 1.30.2.
Published: 2026-07-10
Score: 5.8 Medium
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-w4mc-hhc6-xp28 Mailpit: Incomplete SSRF protection in Link Check API via IPv6 transition mechanisms
History

Fri, 10 Jul 2026 22:00:00 +0000

Type Values Removed Values Added
Description Mailpit is an email testing tool and API for developers. Prior to 1.30.2, the remediation shipped for CVE-2026-27808 is incomplete because the tools.IsInternalIP deny-list in internal/tools/net.go relies on Go's standard library classification helpers and does not block IPv6 transition mechanisms or prefixes such as NAT64, 6to4, IPv4-compatible IPv6, ISATAP, fec0::/10, and 2001:db8::/32. An attacker who can deliver email and invoke POST /api/v1/message/{ID}/link-check can coerce the Link Check API's safeDialContext path into dialing internal destinations and can use status-code and error feedback to map internal service reachability, including cloud metadata endpoints. This issue is fixed in version 1.30.2.
Title Mailpit: Incomplete SSRF protection in Link Check API via IPv6 transition mechanisms (follow-up to CVE-2026-27808)
Weaknesses CWE-918
References
Metrics cvssV3_1

{'score': 5.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N'}

Subscriptions

No data.

cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-07-10T21:43:59.548Z

Reserved: 2026-06-16T15:20:43.086Z

Link: CVE-2026-55187

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

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Weaknesses