CVE-2026-28755

Name: CVE-2026-28755
Creator: NVD / NIST
Published: 2026-03-24T15:16:33.773+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.3/10EPSS 0.13%

Last modified Jun 17, 2026

CVE-2026-28755 is a medium-severity vulnerability rated 5.3/10 on the CVSS scale. 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.. EPSS estimates a 0.13% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1

5.4/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

CVSS 4.0

5.3/10

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

EPSS Probability

0.13%

3.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-863

Affected Software

Vendor	Product	Versions	Update
F5	Nginx Plus	r33	—
F5	Nginx Plus	r34	—
F5	Nginx Plus	r35	P1
F5	Nginx Plus	r36	—
F5	Nginx Open Source	>= 0.5.13, <= 0.9.7	—
F5	Nginx Open Source	>= 1.27.2, < 1.28.3	—
F5	Nginx Open Source	>= 1.29.0, < 1.29.7	—

References

https://my.f5.com/manage/s/article/K000160368Mitigation, Vendor Advisory

Timeline

Published: Mar 24, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-28755?

How severe is CVE-2026-28755?

CVE-2026-28755 has a CVSS score of 5.3/10 (MEDIUM severity). The EPSS model estimates a 0.13% probability of exploitation in the next 30 days.

How do I fix CVE-2026-28755?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-28755?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST