Vulnerability record · CVE-2026-28755 · published 24 March 2026

CVE-2026-28755: F5 nginx plus incorrect authorization vulnerability

F5 · Nginx Plus

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.

5.3 CVSS 4.0 Medium EPSS 0.16% · top 96.1% CWE-863 · Incorrect authorization

5.3CVSS 4.0 base score

0.16%EPSS exploitation probability, 30 days

NoNot in CISA KEV

2Affected product versions listed by NVD

1References

17 Jun 2026Last modified by NVD

Description

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:

Affected products

2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

Nginx Open Source F5

Nginx Plus F5

References

Link	Tags
https://my.f5.com/manage/s/article/K000160368	MitigationVendor Advisory

Track CVE-2026-28755 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

7.5CVE-2023-44487HTTP/2 Rapid Reset stream cancellation denial of serviceThe HTTP/2 protocol permits a client to cancel many streams quickly, and the server's handling of those resets consumes disproportionate resources. T…KEVEPSS 100%analysed10 Oct 2023 9.2CVE-2026-42533F5 nginx gateway fabric heap-based buffer overflow vulnerabilityA vulnerability exists in NGINX Plus and NGINX Open Source when a map directive uses regex matching and a string expression references the map's rege…EPSS 0.89%15 Jul 2026 9.2CVE-2026-42055F5 dos heap-based buffer overflow vulnerabilityNGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_proxy_v2_module and ngx_http_grpc_module modules. This vulnerability exists whe…EPSS 2.4%17 Jun 2026 9.2CVE-2026-42530F5 nginx gateway fabric use after free vulnerabilityNGINX Open Source has a vulnerability in the ngx_http_v3_module module. When NGINX Open Source is configured to use the HTTP/3 QUIC module, a remote …EPSS 1.1%17 Jun 2026 9.2CVE-2026-9256F5 nginx open source heap-based buffer overflow vulnerabilityNGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_rewrite_module module. This vulnerability exists when a rewrite directive uses …EPSS 2.7%22 May 2026 9.2CVE-2026-42945NGINX rewrite module heap buffer overflow via crafted HTTP requestsNGINX Plus and NGINX Open Source contain a heap buffer overflow in the ngx_http_rewrite_module when a rewrite directive is followed by another rewrit…EPSS 3.4%analysed13 May 2026 8.8CVE-2026-60005F5 nginx gateway fabric use of uninitialized resource vulnerabilityNGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_slice_module module. When the slice directive and unnamed regex captures are co…EPSS 0.53%15 Jul 2026 8.8CVE-2026-27654F5 nginx plus heap-based buffer overflow vulnerabilityNGINX Open Source and NGINX Plus have a vulnerability in the ngx_http_dav_module module that might allow an attacker to trigger a buffer overflow to …EPSS 1.5%24 Mar 2026

Source: NIST National Vulnerability Database (record CVE-2026-28755), CISA KEV, FIRST EPSS (scores of 2026-09-28). This page is refreshed as NVD updates the record.