SEPTEMBER 19, 2026
Live Feed
Back to database
Case File

CVE-2026-55187

MEDIUM · CVSS 5.8 EPSS 0.28% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-07-10 · Last synced 2026-08-09

CyberRota Analysis

AI-Generated

Mailpit, an email testing tool for developers, is vulnerable due to an incomplete remediation related to internal IP address filtering, which fails to adequately block certain IPv6 transition mechanisms. This allows attackers to exploit the Link Check API to probe internal services and potentially access sensitive metadata. Organizations using versions prior to 1.30.2 should prioritize upgrading to mitigate the risk of internal service enumeration and exposure.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-55187
Severity
MEDIUM
CVSS
5.8
EPSS
0.28%

Original NVD 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.