CVE-2026-28755 PUBLISHED

NGINX ngx_stream_ssl_module vulnerability

Assigner: f5
Reserved: 18.03.2026 Published: 24.03.2026 Updated: 24.03.2026

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.

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
CVSS Score: 5.4

Attack Vector	Network	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	Low
Privileges Required	Low	Integrity Impact	Low
User Interaction	None	Availability Impact	None

CVSS 3.1

CVSS Vector: 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
CVSS Score: 5.3

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	Low	Confidentiality	None
Attack Complexity	Low	Integrity	Low	Integrity	None
Attack Requirements	None	Availability	None	Availability	None
Privileges Required	Low
User Interaction	None

CVSS 4.0

Product Status

Vendor	F5
Product	NGINX Open Source
Versions	Default: unknown affected from 1.29.0 to 1.29.7 (excl.) affected from 1.27.2 to 1.28.3 (excl.)

Vendor	F5
Product	NGINX Plus
Versions	Default: unknown affected from R36 to R36 P3 (excl.) affected from R35 to R35 P2 (excl.) affected from R34 to * (excl.) affected from R33 to * (excl.)

Credits

Mufeed VH of Winfunc Research reporter

References

https://my.f5.com/manage/s/article/K000160368

Problem Types

CWE-863 Incorrect Authorization CWE