Apache Tomcat - Client certificate verification bypass
Improper Input Validation vulnerability.
This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.14, from 10.1.0-M1 through 10.1.49, from 9.0.0-M1 through 9.0.112.
The following versions were EOL at the time the CVE was created but are known to be affected: 8.5.0 through 8.5.100. Older EOL versions are not affected. Tomcat did not validate that the host name provided via the SNI extension was the same as the host name provided in the HTTP host header field. If Tomcat was configured with more than one virtual host and the TLS configuration for one of those hosts did not require client certificate authentication but another one did, it was possible for a client to bypass the client certificate authentication by sending different host names in the SNI extension and the HTTP host header field.
The vulnerability only applies if client certificate authentication is only enforced at the Connector. It does not apply if client certificate authentication is enforced at the web application.
Users are recommended to upgrade to version 11.0.15 or later, 10.1.50 or later or 9.0.113 or later, which fix the issue.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Java / Kotlin (Maven) | org.apache.tomcat.embed:tomcat-embed-core | >= 11.0.0-M1, < 11.0.15, >= 10.1.0-M1, < 10.1.50, >= 9.0.0-M1, < 9.0.113, >= 8.5.0, <= 8.5.100 | 11.0.15, 10.1.50, 9.0.113 |
| Java / Kotlin (Maven) | org.apache.tomcat:tomcat | >= 11.0.0-M1, < 11.0.15, >= 10.1.0-M1, < 10.1.50, >= 9.0.0-M1, < 9.0.113, >= 8.5.0, <= 8.5.100 | 11.0.15, 10.1.50, 9.0.113 |
| Java / Kotlin (Maven) | org.apache.tomcat:tomcat-coyote | >= 11.0.0-M1, < 11.0.15, >= 10.1.0-M1, < 10.1.50, >= 9.0.0-M1, < 9.0.113, >= 8.5.0, <= 8.5.100 | 11.0.15, 10.1.50, 9.0.113 |
References
- https://nvd.nist.gov/vuln/detail/CVE-2025-66614
- https://github.com/apache/tomcat/commit/152c14885d45f5e0a8b59bd9f93c289cfe20ce30
- https://github.com/apache/tomcat/commit/258a591b61f8cf5c22109e21e5a2a38b63454fd2
- https://github.com/apache/tomcat/commit/5053fa82a1b2b52756810601227984a8b71888a4
- https://github.com/apache/tomcat/commit/9276b5e783c8cd5b3fe2bb716306b65004bdd940
- https://github.com/apache/tomcat/commit/972f9a5e2a07674d92610c478aac1b205d60724e
- https://github.com/apache/tomcat/commit/a4aa74232e826028cd2f7ba0445caf8a8b52c509
- https://github.com/apache/tomcat
- https://lists.apache.org/thread/vw6lxtlh2qbqwpb61wd3sv1flm2nttw7
- https://tomcat.apache.org/security-10.html
- https://tomcat.apache.org/security-11.html
- https://tomcat.apache.org/security-9.html
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N- Weakness (CWE)
CWE-20, CWE-295- Platform
- Java / Kotlin (Maven)
- Package
org.apache.tomcat.embed:tomcat-embed-core, org.apache.tomcat:tomcat, org.apache.tomcat:tomcat-coyote- Disclosed
- 17.02.2026
- Updated
- 11.10.2026 13:20
Sources and licenses
OSV / GitHub Advisory Database - GHSA-fpj8-gq4v-p354 - CC BY 4.0
Vulnerability history: org.apache.tomcat:tomcat-coyote
All published vulnerabilities of this package (Java / Kotlin (Maven)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 33
- First → latest
- 06.2020 05.2026
- Without a fix
- 0
- Exploited in attacks
- 1
Severity breakdown
- Critical 2
- High 17
- Medium 13
- Low 1
Disclosures per year
- 2020: 1
- 2021: 1
- 2022: 8
- 2023: 7
- 2024: 5
- 2025: 4
- 2026: 7
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Apache Tomcat - Client certificate verification bypass this entry
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