Bug 2450779 (CVE-2026-28755)

Summary: CVE-2026-28755 NGINX: NGINX: Certificate revocation bypass when OCSP is enabled
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in NGINX, specifically within its `ngx_stream_ssl_module`. When NGINX is configured to verify client certificates and use the Online Certificate Status Protocol (OCSP) for revocation checks, it fails to properly enforce the revocation status. This allows a Transport Layer Security (TLS) handshake to complete successfully, even if the client's certificate has been identified as revoked. Consequently, systems using revoked certificates may still be able to establish connections, potentially leading to unauthorized access or communication.
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Bug Depends On: 2450844    
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Description OSIDB Bzimport 2026-03-24 15:02:00 UTC
NGINX Plus and NGINX Open Source have a vulnerability in the ngx_stream_ssl_module due to the improper handling of revoked certificates when configured with ssl_verify_client on and ssl_ocsp on, allowing the TLS handshake to succeed even after an OCSP check identifies the certificate as revoked.   


Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.