CVE-2026-40193

maddy is a composable, all-in-one mail server. Versions prior to 0.9.3 contain an LDAP injection vulnerability in the auth.ldap module where user-supplied usernames are interpolated into LDAP search filters and DN strings via strings.ReplaceAll() without any LDAP filter escaping, despite the go-ldap/ldap/v3 library's ldap.EscapeFilter() function being available in the same import. This affects three code paths: the Lookup() filter, the AuthPlain() DN template, and the AuthPlain() filter. An attacker with network access to the SMTP submission or IMAP interface can inject arbitrary LDAP filter expressions through the username field in AUTH PLAIN or LOGIN commands. This enables identity spoofing by manipulating filter results to authenticate as another user, LDAP directory enumeration via wildcard filters, and blind extraction of LDAP attribute values using authentication responses as a boolean oracle or via timing side-channels between the two distinct failure paths. This issue has been fixed in version 0.9.3.

The following products are affected by CVE-2026-40193 vulnerability.

Here, you will find a curated list of external links that provide in-depth information to CVE-2026-40193.

URL	Resource
https://github.com/foxcpp/maddy/commit/6a06337eb41fa87a35697366bcb71c3c962c44ba
https://github.com/foxcpp/maddy/releases/tag/v0.9.3
https://github.com/foxcpp/maddy/security/advisories/GHSA-5835-4gvc-32pc