Medium [CVE-2025-23419] NGINX: When multiple server blocks are configured to share the same IP address and port, an attacker
This medium-severity F5 advisory covers CVE-2025-23419 affecting NGINX.
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Summary
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 are used and/or the 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.
Affected product named by the advisory: NGINX.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · medium-confidence parse· fetched 2 months ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 2 months ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 2 months ago·verify at source
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