#VU124725 LDAP injection in Dovecot and OX Dovecot Pro - CVE-2026-27860
Published: April 1, 2026
Vulnerability identifier: #VU124725
Vulnerability risk: Medium
CVSSv4.0: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-27860
CWE-ID: CWE-90
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerable software:
Dovecot
OX Dovecot Pro
Dovecot
OX Dovecot Pro
Software vendor:
Dovecot
Dovecot
Description
The vulnerability allows a remote attacker to bypass authentication.
The vulnerability exists due to improper neutralization of special elements in an LDAP query within the auth-ldap module when processing usernames. A remote attacker can send a specially crafted request with malicious username when auth_username_chars is empty to probe LDAP structure and potentially bypass authentication.
The server must have auth_username_chars configuration option cleared.
Remediation
Install security update from vendor's website.