axllent Link Check API up to 1.30.1 tools.IsInternalIP internal/tools/net.go safeDialContext {ID} access control

Summaryinfo

A vulnerability has been found in axllent Link Check API up to 1.30.1 and classified as problematic. This affects the function safeDialContext of the file internal/tools/net.go of the component tools.IsInternalIP. Performing a manipulation of the argument {ID} results in access control. This vulnerability is cataloged as CVE-2026-55187. It is possible to initiate the attack remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in axllent Link Check API up to 1.30.1. It has been classified as problematic. This affects the function safeDialContext of the file internal/tools/net.go of the component tools.IsInternalIP. The manipulation of the argument {ID} with an unknown input leads to a access control vulnerability. CWE is classifying the issue as CWE-284. The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. This is going to have an impact on confidentiality. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-55187 since 06/16/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1068 for this issue.

Upgrading to version 1.30.2 eliminates this vulnerability.

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Productinfo

Type

• Automation Software

Vendor

• axllent

Name

• Link Check API

Version

• 1.30.0
• 1.30.1

CPE 2.3info

• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒

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