What’s Vulnerable › Vulnerabilities

CVE-2026-86009: Mailu: Domain managers can allow themselves to spoof on other hosted domains they should not control

• Severity: high (CVSS 8.2 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-16 · updated 2026-10-21
• Weakness: CWE-285

Description

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.

Affected products

• Mailu: before f05aeb8322e2f61096af6b089d61ba6f40587d96

References

• https://github.com/Mailu/Mailu/commit/f05aeb8322e2f61096af6b089d61ba6f40587d96
• https://github.com/Mailu/Mailu/issues/2686
• https://github.com/Mailu/Mailu/pull/4072
• https://github.com/Mailu/Mailu/security/advisories/GHSA-crww-m82r-2wfm
• https://github.com/Mailu/Mailu/issues/2686

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