Severity: moderate
Affected versions:
- Apache Karaf (org.apache.karaf.jaas.modules.ldap) before 4.4.12
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 than the intended one, over-granting roles, and depending on
deployment-specific filter templates, potentially affecting which account a
login resolved to.
It's not exploitable through every entry points: LDAPLoginModule and
LDAPPubkeyLoginModule both called Util.doRFC2254Encoding() (correct RFC 4515
escaping) on the login name before handing it to LDAPCache, which masked the
missing escaping in LDAPCache for those two call paths. Using LDAPCache
directly (bypassing the login modules) does not reproduce through the normal
LDAPLoginModule/LDAPPubkeyLoginModule authentication flow for this reason. It
does reproduce through two other call paths that reach
LDAPCache/LDAPBackingEngine without any prior escaping:
* GSSAPILdapLoginModule passes the NameCallback name straight through,
unescaped.
* LDAPBackingEngine (listRoles) passes principal.getName() straight through,
unescaped.
This issue is being tracked as https://github.com/apache/karaf/pull/2880
Credit:
Gjoko Krstic <[email protected]> (reporter)
References:
https://karaf.apache.org/
https://www.cve.org/CVERecord?id=CVE-2026-90979
https://issues.apache.org/jira/browse/https://github.com/apache/karaf/pull/2880
