Vulnerability · Published Sep 2, 2026 · Assigned by VulnCheck

CVE-2026-84697Mailpit SSRF Deny List Bypass via Azure Metadata and IPv6 Prefix

Medium 5.3

In plain English

A medium-severity server-side request forgery in mailpit from axllent. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 34% of all known vulnerabilities).

Severity (CVSS 3.1)5.3Medium

Exploit odds (30 days)0.4%top 65.9% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

Vendor	Product	Versions
axllent	mailpit	0 – through 1.31.0

Weakness: CWE-918 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

References

https://github.com/axllent/mailpit product
Patch Commit patch
https://github.com/axllent/mailpit/blob/v1.31.0/internal/tools/net.go technical-description
VulnCheck Advisory: Mailpit SSRF Deny List Bypass via Azure Metadata and IPv6 Prefix third-party-advisory