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Nginx Open Source CVE-2026-28755

| EUVDEUVD-2026-14887 MEDIUM
Incorrect Authorization (CWE-863)
2026-03-24 f5 GHSA-hgfr-jmpr-2p89
5.3
CVSS 4.0 · NVD
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Severity by source

NVD PRIMARY
5.3 MEDIUM
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
SUSE
5.4 MEDIUM
AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
Red Hat
5.4 MEDIUM
qualitative

Primary rating from NVD.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
X

Lifecycle Timeline

4
Patch released
Apr 11, 2026 - 08:30 nvd
Patch available
EUVD ID Assigned
Mar 24, 2026 - 14:45 euvd
EUVD-2026-14887
Analysis Generated
Mar 24, 2026 - 14:45 vuln.today
CVE Published
Mar 24, 2026 - 14:13 nvd
MEDIUM 5.3

DescriptionCVE.org

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.

AnalysisAI

NGINX Plus and NGINX Open Source contain an authentication bypass vulnerability in the ngx_stream_ssl_module where revoked certificates are incorrectly accepted during TLS handshakes despite OCSP checking. When ssl_verify_client and ssl_ocsp are both enabled, the module fails to properly enforce certificate revocation status, allowing clients with revoked certificates to establish connections. This affects both commercial NGINX Plus and open-source NGINX deployments with a CVSS score of 5.4 (Medium), representing a localized confidentiality and integrity impact requiring authenticated attackers.

Technical ContextAI

The vulnerability exists in NGINX's stream SSL module (ngx_stream_ssl_module), which handles TLS certificate validation for stream-based connections. The root cause is classified under CWE-863 (Incorrect Authorization), specifically involving improper handling of certificate revocation status returned by OCSP (Online Certificate Status Protocol) responders. When both ssl_verify_client (which requires client certificate validation) and ssl_ocsp (which enables OCSP stapling/checking) directives are enabled, the module fails to deny the handshake when OCSP responses indicate a revoked certificate. This affects CPE entries cpe:2.3:a:f5:nginx_open_source:*:*:*:*:*:*:*:* and cpe:2.3:a:f5:nginx_plus:*:*:*:*:*:*:*:*, indicating the flaw impacts all versions across both product lines (subject to End of Technical Support constraints).

RemediationAI

Apply the security patch provided by F5 for NGINX Plus and NGINX Open Source via the official security advisory at https://my.f5.com/manage/s/article/K000160368, ensuring your specific NGINX version has an available patch and has not reached End of Technical Support. Until patching is possible, implement compensating controls by disabling ssl_ocsp temporarily if your threat model permits, enforcing certificate pinning at the application layer, or restricting client certificate acceptance to pre-approved certificate fingerprints and serial numbers maintained in an allowlist. For production environments using mutual TLS, consider implementing a reverse proxy or WAF capable of performing independent OCSP validation and certificate revocation checks before allowing connections to reach NGINX.

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Heap buffer overflow in NGINX Plus and NGINX Open Source lets unauthenticated remote attackers crash worker processes (D

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Limited memory disclosure and worker-process restart in NGINX Plus and NGINX Open Source arise when the optional ngx_htt

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Integer overflow in NGINX 32-bit builds with the ngx_http_mp4_module allows local attackers to corrupt or overwrite work

CVE-2026-32647 HIGH
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NGINX Open Source and NGINX Plus contain a buffer over-read or over-write vulnerability in the ngx_http_mp4_module that

CVE-2026-56434 HIGH
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Heap buffer over-read in the ngx_http_ssi_module of NGINX Open Source and NGINX Plus lets an unauthenticated man-in-the-

CVE-2026-42946 HIGH
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Memory disclosure and denial-of-service in NGINX's SCGI and uWSGI proxy modules allow attackers with man-in-the-middle p

Vendor StatusVendor

SUSE

Severity: Medium
Product Status
openSUSE Tumbleweed Fixed
SUSE Linux Enterprise High Performance Computing 15 SP7 Fixed
SUSE Linux Enterprise Module for Server Applications 15 SP7 Fixed
SUSE Linux Enterprise Server 15 SP7 Fixed
SUSE Linux Enterprise Server 16.0 Fixed

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CVE-2026-28755 vulnerability details – vuln.today

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