CVE-2026-73644 is a critical-severity (CVSS 9.6) CWE-285 vulnerability in org.openidentityplatform.opendj:opendj-server-legacy. O3 Security confirms whether CVE-2026-73644 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
OpenDJ SASL PLAIN authzid bypassing the proxy ACI scope check
Real-World Exposure
org.openidentityplatform.opendj:opendj-server-legacyReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
Summary
When a SASL PLAIN bind supplies an authorization identity (authzid) that resolves to a different user, PlainSASLMechanismHandler verified only the PROXIED_AUTH privilege and never evaluated the "proxy" access-control right (the mayProxy ACI scope check). As a result, any account holding the proxied-auth privilege could assume any resolvable non-root identity without being granted a proxy ACI for that target.
This diverges from every other proxy path in OpenDJ — the proxied-authorization controls (RFC 4370) and the DIGEST-MD5 / GSSAPI authzid handlers all require both the privilege and the mayProxy scope grant.
Impact
Privilege escalation / authorization bypass: a holder of proxied-auth can act as arbitrary directory users beyond the scope intended by the deployment's proxy ACIs, defeating the ACI-based restriction on which identities may be impersonated. Root/Directory Manager is not assumable this way.
Fix
Enforce the mayProxy scope check on the SASL PLAIN authzid path (both dn: and u:/bare forms), sharing one hasProxyAccess helper with the DIGEST-MD5/GSSAPI path. Denial returns INVALID_CREDENTIALS (49) before password verification — matching DIGEST-MD5/GSSAPI — so an unauthenticated client cannot distinguish a missing privilege from a missing ACI grant.
Workaround
Restrict or revoke the proxied-auth privilege until upgraded.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.openidentityplatform.opendj:opendj-server-legacy | all versions | 5.1.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.openidentityplatform.opendj:opendj-server-legacy. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update org.openidentityplatform.opendj:opendj-server-legacy to 5.1.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-73644 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-73644 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-73644. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-73644 in your dependencies?
O3 detects CVE-2026-73644 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.