CVE-2026-90979

/// Technical description

LDAPCache and LDAPBackingEngine build LDAP search filters for user lookup and role lookup by textually substituting the placeholders %u, %dn, and %fqdn (drawn from the login name, the resolved user DN, and its fully qualified namespace form) into administrator-configured filter templates (userFilter, roleFilter). Before the fix, the only sanitization applied to the substituted value was double backslashed:

filter = filter.replaceAll(Pattern.quote("%u"), Matcher.quoteReplacement(user));

filter = filter.replace("\\", "\\\\");

This does not escape the other characters RFC 4515 requires escaping in an LDAP search filter: *, (, ), and NUL. A login name containing any of these can change the structure of the resulting filter rather than being matched as a literal value (e.g. a crafted username can turn an equality match into a wildcard match, or close/reopen filter clauses), widening what the search returns and potentially causing a login or role lookup to match an LDAP entry other tha

/// Remediation

Check the references section for vendor advisories and patches from apache. Update karaf to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// Affected products

/// References