Nginx: TLS Session Resumption Vulnerability (CVE-2025-23419)
A vulnerability in nginx allows an attacker to bypass client certificate authentication when multiple server blocks share the same IP address and port using TLS session resumption. This occurs when TLS Session Tickets or SSL session cache are used in the default server performing client certificate authentication. The issue affects multiple nginx versions and has a moderate security impact. A patch is available from Red Hat and users are advised to update to fixed versions.
AI Analysis
Technical Summary
CVE-2025-23419 is a TLS session resumption vulnerability in nginx that arises when multiple server blocks share the same IP address and port. If TLS Session Tickets or SSL session cache are enabled in the default server performing client certificate authentication, an attacker can bypass the client certificate authentication requirements on these servers. This vulnerability affects nginx versions including but not limited to >=1.11.4 <1.26.3, >=9.0.0 <9.6, and >=1.27.0 <1.27.4. Red Hat has issued a security advisory (RHSA-2025:7331) providing patches to address this moderate severity issue.
Potential Impact
The vulnerability allows an attacker to bypass client certificate authentication on nginx servers configured with multiple server blocks sharing the same IP and port, potentially allowing unauthorized access to resources protected by client certificate authentication. This undermines the intended security controls relying on client certificates.
Mitigation Recommendations
A patch is available and should be applied to affected nginx versions. Red Hat provides updated packages for Red Hat Enterprise Linux 9 and related distributions. Users should follow the update instructions in the Red Hat advisory RHSA-2025:7331 and the linked article https://access.redhat.com/articles/11258 to remediate this vulnerability. No alternative mitigations are indicated in the advisory.
Nginx: TLS Session Resumption Vulnerability (CVE-2025-23419)
Description
A vulnerability in nginx allows an attacker to bypass client certificate authentication when multiple server blocks share the same IP address and port using TLS session resumption. This occurs when TLS Session Tickets or SSL session cache are used in the default server performing client certificate authentication. The issue affects multiple nginx versions and has a moderate security impact. A patch is available from Red Hat and users are advised to update to fixed versions.
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2025-23419 is a TLS session resumption vulnerability in nginx that arises when multiple server blocks share the same IP address and port. If TLS Session Tickets or SSL session cache are enabled in the default server performing client certificate authentication, an attacker can bypass the client certificate authentication requirements on these servers. This vulnerability affects nginx versions including but not limited to >=1.11.4 <1.26.3, >=9.0.0 <9.6, and >=1.27.0 <1.27.4. Red Hat has issued a security advisory (RHSA-2025:7331) providing patches to address this moderate severity issue.
Potential Impact
The vulnerability allows an attacker to bypass client certificate authentication on nginx servers configured with multiple server blocks sharing the same IP and port, potentially allowing unauthorized access to resources protected by client certificate authentication. This undermines the intended security controls relying on client certificates.
Mitigation Recommendations
A patch is available and should be applied to affected nginx versions. Red Hat provides updated packages for Red Hat Enterprise Linux 9 and related distributions. Users should follow the update instructions in the Red Hat advisory RHSA-2025:7331 and the linked article https://access.redhat.com/articles/11258 to remediate this vulnerability. No alternative mitigations are indicated in the advisory.
Technical Details
- Gcve Source
- db.gcve.eu
- Csaf Category
- csaf_security_advisory
- Csaf Version
- 2.0
- Publisher
- Red Hat Product Security
- Advisory Id
- RHSA-2025:7331
- Cve Count
- 1
Threat ID: 6a3da1d34853345fc1826206
Added to database: 06/25/2026, 21:46:59 UTC
Last enriched: 09/08/2026, 15:18:54 UTC
Last updated: 09/10/2026, 19:36:49 UTC
Views: 28
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