CVE-2026-86009

What it is

Mailu is a mail server distributed as a set of Docker images. Prior to f05aeb8322e2f61096af6b089d61ba6f40587d96, domain managers can enable spoofing for hosted domains they do not control. A potentially malicious domain administrator enables spoofing for another hosted domain and can send emails that are authenticated with DKIM/SPF for domains they should not be able to. This vulnerability is addressed by f05aeb8322e2f61096af6b089d61ba6f40587d96.

At a glance

Exploitability

Can be exploited over the network with an admin-level account. High risk of data tampering.

Exploit odds

0.4% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-10-16 17:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-21 03:17 UTC Last updatedMost recent change to the record

Details

Published

2026-10-16 17:17 UTC

Last modified

2026-10-21 03:17 UTC

Exploit probability

0.4% · EPSS, next 30 days

Weakness

CWE-285

Record status

Deferred

Attack profile CVSS 4.0 · 8.2

Attack vector

Network

Complexity

Low

Attack requirements

None

Privileges needed

High

User interaction

None

Confidentiality

None

Integrity

High

Availability

None