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Description

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.

PUBLISHED Reserved 2026-04-09 | Published 2026-04-15 | Updated 2026-04-16 | Assigner GitHub_M




HIGH: 8.2CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N

Problem types

CWE-90: Improper Neutralization of Special Elements used in an LDAP Query ('LDAP Injection')

Product status

< 0.9.3
affected

References

github.com/.../maddy/security/advisories/GHSA-5835-4gvc-32pc

github.com/...ommit/6a06337eb41fa87a35697366bcb71c3c962c44ba

github.com/foxcpp/maddy/releases/tag/v0.9.3

cve.org (CVE-2026-40193)

nvd.nist.gov (CVE-2026-40193)

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