CVE-2025-23419
TLS Session Resumption Vulnerability
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.
How to fix CVE-2025-23419
To remediate CVE-2025-23419, upgrade the affected package to a fixed version below.
- —upgrade to 1.26.3-r0 or later
- —upgrade to 1.26.3 or later
- —upgrade to 1.26.3 or later
- —upgrade to 1.18.0-6.1+deb11u4 or later
Is CVE-2025-23419 being exploited?
Low — EPSS is 2.9%, meaning exploitation activity has not been observed at scale.
Affected packages (4)
- from 0, < 1.26.3-r0
- >= 1.11.4, < 1.26.3, >= 1.27.0, < 1.27.4
- >= 1.11.4, < 1.26.3, >= 1.27.0, < 1.27.4
- from 0, < 1.18.0-6.1+deb11u4
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | 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/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 |