CVE-2026-50623 — cxf-rt-rs-security-oauth2
MEDIUMCVE-2026-50623 is a medium-severity (CVSS 4.8) Improper Authentication vulnerability in org.apache.cxf:cxf-rt-rs-security-oauth2. A fix is available for org.apache.cxf:cxf-rt-rs-security-oauth2 — see the affected versions and patch details below.
Apache CXF: Authentication Bypass in OAuth2 TokenIntrospectionService
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-50623.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-50623 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 382,621 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
org.apache.cxf:cxf-rt-rs-security-oauth2☕org.apache.cxf:cxf-rt-rs-security-oauth2Real-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
An authentication bypass vulnerability exists in the OAuth2 TokenIntrospectionService in Apache CXF. Due to a missing 'throw' keyword in the security context check, the introspection endpoint (/services/oauth2/introspect) can be accessed by any unauthenticated network attacker. However note that this is a safeguard only in the case that someone forgot to enable authentication on the service. Users are recommended to upgrade to version 4.2.2 or 4.1.7 or 3.6.12, which fixes this issue.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.apache.cxf:cxf-rt-rs-security-oauth2 | ≥ 4.2.0&&< 4.2.2 | 4.2.2org.apache.cxf:cxf-rt-rs-security-oauth2:4.2.2 |
| ☕Maven | org.apache.cxf:cxf-rt-rs-security-oauth2 | all versions | 4.1.7org.apache.cxf:cxf-rt-rs-security-oauth2:4.1.7 |
Affected Products
cxfapacheDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.cxf:cxf-rt-rs-security-oauth2, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.apache.cxf:cxf-rt-rs-security-oauth2 to 4.2.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-50623 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.
Frequently Asked Questions
Is CVE-2026-50623 in your dependencies?
Find it across Maven, including transitive dependencies.