CVE-2026-27860 Other in OX Dovecot Pro

Low 3.7 Published 27 Mar 2026 Updated 27 Mar 2026

Attackers can inject LDAP filters to bypass restrictions and probe structure if auth_username_chars is empty in Dovecot.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2026-27860?

CVE-2026-27860 is a low-severity vulnerability in Dovecot Dovecot, published on 27 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

If auth_username_chars is empty, it is possible to inject arbitrary LDAP filter to Dovecot's LDAP authentication. This leads to potentially bypassing restrictions and allows probing of LDAP structure. Do not clear out auth_username_chars, or install fixed version. No publicly available exploits are known.

Weakness: CWE-90

Which versions are affected by CVE-2026-27860?

It affects 2 products.

Products include Dovecot Dovecot, Open-Xchange Dovecot.

How do I fix CVE-2026-27860?

Change a configuration setting.

Is CVE-2026-27860 being exploited?

There is no known exploitation of CVE-2026-27860 in the wild and no public exploit code.

All Dovecot Dovecot vulnerabilities

Sources

Also known as ALPINE-CVE-2026-27860, AZL-81716, DEBIAN-CVE-2026-27860, GHSA-3322-wpc2-p4m7, UBUNTU-CVE-2026-27860.