CVE-2026-40193
Maddy Mail Server has an LDAP Filter Injection via Unsanitized Username
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| go | github.com/foxcpp/maddy | < 0.9.3 | 0.9.3 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Maddy Project | Maddy | before 0.9.3 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- 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
- https://github.com/advisories/GHSA-5835-4gvc-32pc
- https://nvd.nist.gov/vuln/detail/CVE-2026-40193