Certificate Revocation Vulnerability in NGINX Plus and Open Source
CVE-2026-28755

5.3MEDIUM

Key Information:

Vendor

F5
Status
Nginx Open Source
Nginx Plus
Vendor
CVE Published:
24 March 2026

What is CVE-2026-28755?

NGINX Plus and NGINX Open Source are impacted by a vulnerability in the ngx_stream_ssl_module that arises from improper management of revoked certificates. When both ssl_verify_client and ssl_ocsp directives are enabled, the system may incorrectly allow a TLS handshake to proceed even if an OCSP check indicates that the certificate has been revoked. This flaw can lead to significant security risks by permitting potentially unauthorized access, thereby undermining the integrity of secure communications.

Affected Version(s)

NGINX Open Source 1.29.0 < 1.29.7

NGINX Open Source 1.27.2 < 1.28.3

NGINX Plus R36

References

https://my.f5.com/manage/s/article/K000160368
vendor-advisory

CVSS V4

Score:
5.3
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
Low
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Mufeed VH of Winfunc Research
.