F5 NGINX Open Source/NGINX Plus ngx_stream_ssl_module authorization

CVSS Meta Temp Score
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CTI Interest Score
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5.6$0-$5k0.00

Summaryinfo

A vulnerability classified as critical was found in F5 NGINX Open Source and NGINX Plus. Impacted is the function ngx_stream_ssl_module. Executing a manipulation can lead to authorization. This vulnerability is handled as CVE-2026-28755. The attack can be executed remotely. There is not any exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability has been found in F5 NGINX Open Source and NGINX Plus (version unknown) and classified as critical. This vulnerability affects the function ngx_stream_ssl_module. The manipulation with an unknown input leads to a authorization vulnerability. The CWE definition for the vulnerability is CWE-863. The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. This allows attackers to bypass intended access restrictions. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

NGINX Plus and NGINX Open Source have a vulnerability in the ngx_stream_ssl_module module due to the improper handling of revoked certificates when configured with the ssl_verify_client on and ssl_ocsp on directives, 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.

The advisory is available at my.f5.com. This vulnerability was named CVE-2026-28755 since 03/18/2026. The exploitation appears to be easy. The attack can be initiated remotely. Technical details are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 306672 (nginx 1.27.2 < 1.28.3 / 1.29.x < 1.29.7 OCSP Result Bypass), which helps to determine the existence of the flaw in a target environment.

Upgrading eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (306672) and CERT Bund (WID-SEC-2026-0860). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Affected

  • Debian Linux
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Fedora Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • RESF Rocky Linux
  • NGINX NGINX Plus
  • NGINX NGINX

Productinfo

Type

Vendor

Name

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 5.7
VulDB Meta Temp Score: 5.6

VulDB Base Score: 6.3
VulDB Temp Score: 6.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 5.4
NVD Vector: 🔒

CNA Base Score: 5.4
CNA Vector: 🔒

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Authorization
CWE: CWE-863 / CWE-285 / CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 306672
Nessus Name: nginx 1.27.2 < 1.28.3 / 1.29.x < 1.29.7 OCSP Result Bypass

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Timelineinfo

03/18/2026 CVE reserved
03/24/2026 +6 days Advisory disclosed
03/24/2026 +0 days VulDB entry created
05/20/2026 +57 days VulDB entry last update

Sourcesinfo

Vendor: f5.com

Advisory: K000160368
Status: Confirmed

CVE: CVE-2026-28755 (🔒)
GCVE (CVE): GCVE-0-2026-28755
GCVE (VulDB): GCVE-100-352786
CERT Bund: WID-SEC-2026-0860 - NGINX und NGINX Plus: Mehrere Schwachstellen

Entryinfo

Created: 03/24/2026 16:08
Updated: 05/20/2026 11:32
Changes: 03/24/2026 16:08 (74), 03/28/2026 20:34 (12), 04/14/2026 04:06 (7), 04/17/2026 01:08 (2), 05/20/2026 11:32 (1)
Complete: 🔍
Cache ID: 216::103

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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