mTLS bypass via inconsistent FQDN normalization
Published Feb 17, 2022 · Updated Apr 23, 2025
Improper TLS configuration selection in Traefik Labs Traefik Proxy before 2.6.1 allows remote attackers to bypass route-level mTLS. The HTTP router normalizes a trailing-dot FQDN differently from TLS option lookup, causing the request to use default TLS options instead of the router's dedicated policy. Exposure requires a router with dedicated mTLS options and an FQDN host form or CNAME flattening, enabling access to protected services without the required client certificate.
Summary
What happened
Improper TLS configuration selection in Traefik Labs Traefik Proxy before 2.6.1 allows remote attackers to bypass route-level mTLS. The HTTP router normalizes a trailing-dot FQDN differently from TLS option lookup, causing the request to use default TLS options instead of the router's dedicated policy. Exposure requires a router with dedicated mTLS options and an FQDN host form or CNAME flattening, enabling access to protected services without the required client certificate.
The record
- CVE
- CVE-2022-23632
- Published
- Feb 17, 2022
- Updated
- Apr 23, 2025
- Vendor
- Traefik Labs
- Product
- Traefik Proxy
- Classifications
- CWE-295, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 17, 2022CVE publishedPublication date reported by the CVE source.
- Apr 23, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 2.6.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
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
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo