CVE-2026-84697

Mailpit's IsInternalIP deny list function fails to block the Azure WireServer address 168.63.129.16 and the RFC 2765/6145 IPv4-translated IPv6 prefix, allowing server-side request forgery to internal destinations. Attackers can supply hostnames resolving to these addresses in message content to reach the link check API and proxy endpoint for accessing internal resources.

  • Published Sep 2, 2026
  • CVSS 6.9 medium
  • 0.4% chance of exploitation in the next 30 days (EPSS)
  • A fix is available

Affected software

CVE-2026-84697 at the National Vulnerability Database