Server-Side Request Forgery Vulnerability in Mailpit Web Application
CVE-2026-84697

6.9MEDIUM

Key Information:

Vendor

Axllent

Status
Mailpit
Vendor
CVE Published:
2 September 2026

What is CVE-2026-84697?

A vulnerability in Mailpit's IsInternalIP deny list function allows attackers to bypass security measures, enabling server-side request forgery (SSRF) to internal destinations. The flaw specifically fails to block requests to the Azure WireServer address (168.63.129.16) and the IPv4-translated IPv6 prefix as defined by RFC 2765 and RFC 6145. Exploiting this vulnerability, attackers can manipulate hostnames in message content to access internal resources via the link check API and proxy endpoint, potentially leading to severe security breaches.

Affected Version(s)

mailpit 0 <= 1.31.0

References

https://github.com/axllent/mailpit
product
https://github.com/axllent/mailpit/commit/a02821bf3424da9...
patch
https://github.com/axllent/mailpit/blob/v1.31.0/internal/...
technical-description

CVSS V4

Score:
6.9
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

euriconicacio
.