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.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact Low

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact Low

Integrity Impact None

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
axllent mailpit unaffected
Version Status Constraints
0 affected ≤ 1.31.0

No data.

No data.

No data.

Project Subscriptions

Vendors Products
Axllent Subscribe
Mailpit Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/axllent/mailpit cve-icon cve-icon
https://github.com/axllent/mailpit/blob/v1.31.0/internal/tools/net.go cve-icon cve-icon
https://github.com/axllent/mailpit/commit/a02821bf3424da9196e156c422370f4868a1dff2 cve-icon cve-icon
https://www.vulncheck.com/advisories/mailpit-ssrf-deny-list-bypass-via-azure-metadata-and-ipv6-prefix cve-icon cve-icon
History

Wed, 02 Sep 2026 01:15:00 +0000

Type Values Removed Values Added
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.
Title Mailpit SSRF Deny List Bypass via Azure Metadata and IPv6 Prefix
First Time appeared Axllent
Axllent mailpit
Weaknesses CWE-918
CPEs cpe:2.3:a:axllent:mailpit:*:*:*:*:*:*:*:*
Vendors & Products Axllent
Axllent mailpit
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N'}

cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-09-02T00:37:53.020Z

Reserved: 2026-09-01T23:24:24.109Z

Link: CVE-2026-84697

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-02T01:17:24.703

Modified: 2026-09-02T01:17:24.703

Link: CVE-2026-84697

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses