CVE-2026-104939
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk28th percentile - higher than 28% of all known CVEs
Summary
NGINX Ingress Controller has a vulnerability when implementing an externalAuth policy for ingress. NGINX Ingress Controller may mishandle the HTTP response from an OAuth IdP and allow an attacker to acquire unauthenticated access to protected paths before the proper external authentication can happen.
Risk Assessment
A remote attacker may gain unauthenticated access to protected paths, constituting an access control breach. This is a data plane issue only, with no control plane exposure.
Recommendation
Update NGINX Ingress Controller to a version containing the fix. Review externalAuth policy configurations and verify that protected paths are properly secured.
Other vulnerabilities in NGINX Ingress Controller
See all- CVE-2026-77180High
A vulnerability in NGINX Ingress Controller where the configuration generator does not sanitize user-controllable fields from Ingress annotations. An authenticated attacker with permission to create or modify these annotations can inject arbitrary NGINX configuration directives.
- CVE-2026-55723High
An injection vulnerability exists in NGINX Ingress Controller when configured with CRDs or Ingress annotations. An authenticated attacker with write access can inject arbitrary NGINX configuration directives.
- CVE-2026-52865Medium
A vulnerability in NGINX Ingress Controller allows an authenticated attacker with permissions to create or modify Ingress or TransportServer resources to terminate the controller process. This causes a persistent crash loop until the malformed resource is removed from the cluster.
Original NVD description (English source)
Description NGINX Ingress Controller has a vulnerability when implementing an externalAuth policy for ingress. NGINX Ingress Controller may mishandle the HTTP response from an OAuth IdP and allow an attacker to acquire unauthenticated access to protected paths before the proper external authentication can happen. Impact This vulnerability may allow remote attackers unauthenticated access to protected paths. There is no control plane exposure; this is a data plane issue only. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS