CVE-2026-73644: OpenDJ: Authorization bypass in SASL PLAIN allowing a `proxied-auth` holder to impersonate any resolvable non-root user without an ACI proxy grant
OpenDJ is an LDAPv3 compliant directory service. Prior to 5.1.2, the SASL PLAIN authorization identity path in opendj-server-legacy/src/main/java/org/opends/server/extensions/PlainSASLMechanismHandler.java checked the PROXIEDAUTH privilege but did not evaluate the mayProxy proxy ACI scope when an authzid resolved to a different user. Both dn: and u: or bare authzid forms could therefore let an authenticated account holding PROXIEDAUTH assume any resolvable non-root identity outside the identities permitted by its proxy ACI. The fix returns INVALIDCREDENTIALS (49) before password verification when the target authorization identity is not permitted. This issue is fixed in version 5.1.2.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
opendj-server-legacy/src/main/java/org/opends/server/extensions/PlainSASLMechanismHandler.java / OpenDJto a version that resolves this vulnerability.Fixed in 5.1.2 - Compensating control
If upgrading to OpenDJ 5.1.2 is not immediately possible, ensure that proxy ACI mayProxy scope for any proxied-auth holders is limited so they cannot resolve an authzid to other non-root identities outside their permitted proxy ACI scope.