---
cve: "CVE-2026-55187"
severity: "MEDIUM"
cvss: 5.8
epss: "28%"
vendor: "axllent"
kev: false
exploited: false
published: "2026-07-10 22:16:43"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-08T09:17:47+02:00"
---

# CVE-2026-55187

> 5.8 MEDIUM · 🧪 PoC

## Beschreibung

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.

## CVSS-Vektor

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

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Verändert | bad |
| C Vertraulichkeit | Gering | warn |
| I Integrität | Keine | good |
| A Verfügbarkeit | Keine | good |

## Patch verfügbar (OSV)

- a88dadbbe1df016a35a445089ef2a362a6c2de78 (Commit)
- 0fb1c79f4bf75418e138424f276f48b4aa4f802b (Commit)

## Referenzen

- <https://github.com/axllent/mailpit/security/advisories/GHSA-w4mc-hhc6-xp28>
- <https://github.com/axllent/mailpit/commit/a88dadbbe1df016a35a445089ef2a362a6c2de78>
- <https://github.com/axllent/mailpit/releases/tag/v1.30.2>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-55187) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_