CVE-2025-23419Network attack vector

Client-certificate bypass via cross-host TLS session reuse

Published Feb 5, 2025 · Updated Jan 23, 2026

Authentication bypass in F5 NGINX Open Source and NGINX Plus allows remote authenticated users to read client-certificate-protected content. The TLS 1.3 session-resumption path accepts a session established for one name-based virtual host in another host's context without repeating its client-certificate check. Exposure requires shared IP and port listeners, an OpenSSL build, TLS 1.3, session tickets or caching, and client-certificate authentication on the default server.

CVSS severity5.3
Medium
EPSS probability2.79%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in F5 NGINX Open Source and NGINX Plus allows remote authenticated users to read client-certificate-protected content. The TLS 1.3 session-resumption path accepts a session established for one name-based virtual host in another host's context without repeating its client-certificate check. Exposure requires shared IP and port listeners, an OpenSSL build, TLS 1.3, session tickets or caching, and client-certificate authentication on the default server.

The record

CVE
CVE-2025-23419
Published
Feb 5, 2025
Updated
Jan 23, 2026
Vendor
F5 Networks
Product
NGINX Open Source
Classifications
CWE-863, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 5, 2025CVE publishedPublication date reported by the CVE source.
  2. Jan 23, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.11.4 <* changes=[{"at":"1.27.4","status":"unaffected"},{"at":"1.26.3","status":"unaffected"}]

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

F5 Networks · NGINX Open Sourceversion=1.11.4 <* changes=[{"at":"1.27.4","status":"unaffected"},{"at":"1.26.3","status":"unaffected"}]
F5 Networks · NGINX Plusversion=R17 <* changes=[{"at":"R32 P2","status":"unaffected"},{"at":"R33 P2","status":"unaffected"}]

Published CVSS scores

4.3F5 NetworksCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
5.3F5 NetworksCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-863Incorrect Authorization
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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