CVE-2025-23419

TLS Session Resumption Vulnerability

State: Published
Severity: 5.3 Medium
Published: Feb 5, 2025
Updated: Jan 23, 2026
Reserved: Jan 22, 2025

Description

When multiple server blocks are configured to share the same IP address and port, an attacker can use session resumption to bypass client certificate authentication requirements on these servers. This vulnerability arises when TLS Session Tickets https://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_session_ticket_key are used and/or the SSL session cache https://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_session_cache are used in the default server and the default server is performing client certificate authentication.

Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Scores

CVSS	Score	Vector	Source
4.0	5.3 Medium	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N	f5
3.1	4.3 Medium	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N	f5

Weaknesses

CWE-863 Incorrect Authorization

Affected Products

Product	Versions
NGINX Open SourceF5	1.11.4 and laterAffectedfrom 1.27.4Not affectedfrom 1.26.3Not affected
NGINX PlusF5	R17 and laterAffectedfrom R32 P2Not affectedfrom R33 P2Not affected

References

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