CVE-2026-104939

HIGHCVSS 7.5/10EPSS 0.36%

Last modified

CVE-2026-104939 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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.. EPSS estimates a 0.36% chance of exploitation in the next 30 days.

Description

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.

Metrics

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
F5NGINX Ingress Controller>= 5.6.0, < 5.7.0

References

Timeline

Published
Last Modified
Status
Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-104939?
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.
How severe is CVE-2026-104939?
CVE-2026-104939 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.36% probability of exploitation in the next 30 days.
How do I fix CVE-2026-104939?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST