This vulnerability allows unauthenticated clients to exploit the ACME TLS-ALPN fast path in Traefik, which is an HTTP reverse proxy and load balancer. Specifically, prior to versions 2.11.35 and 3.6.7, a malicious client can create many connections and send a minimal ClientHello with acme-tls/1, then stop responding. This can tie up go routines and file descriptors indefinitely, ultimately leading to denial of service for the entry point.
The CVSS score for this vulnerability is 5.9, indicating a medium severity level. Although it does not pose a direct risk to confidentiality or integrity, the potential impact on availability is significant. Organizations utilizing Traefik should address this issue promptly, as it could lead to severe disruptions in service.
The vulnerability was published on January 15, 2026, and has been analyzed. The urgency for defenders is high, and organizations should prioritize patching immediately to mitigate the risk of exploitation.
The vulnerability is fixed in versions 2.11.35 and 3.6.7. Administrators should ensure that their Traefik installations are updated to these versions or later.
Vulnerability Details
The official CVE description states that there is a potential vulnerability in Traefik's automatic generation of ACME TLS certificates. The vulnerability allows unauthenticated clients to tie up resources, resulting in a denial of service.
This vulnerability is classified under CWE-770, indicating improper resource management. The CVSS score assigned to this vulnerability is 5.9, which falls in the medium severity category. The vulnerability affects Traefik software versions prior to 2.11.35 and 3.6.7.
The publication date of this CVE was January 15, 2026, and it is important to note that organizations should remain vigilant and ensure that they are using the latest patched versions to avoid potential exploitation.
Technical Analysis
The root cause of this vulnerability lies in the handling of ACME TLS challenges. When the ACME TLS challenge is enabled, a malicious client can open multiple connections and send a minimal ClientHello, which can lead to resource exhaustion. This vulnerability is characterized by high attack complexity, requiring no privileges or user interaction for exploitation.
The attack vector for this vulnerability is network-based, allowing attackers to exploit it remotely. The potential impact on availability is high, as it can lead to service outages. Organizations should assess their configurations and consider implementing network controls to mitigate this risk.
Risk & Impact Analysis
Risk to organizations includes potential service disruptions due to denial of service attacks utilizing this vulnerability. As Traefik is commonly used for routing and load balancing in modern applications, the blast radius could be significant, affecting multiple services and users.
Given the medium CVSS score, organizations should address this vulnerability in their priority patch cycle. The urgency is underscored by the potential for widespread impact if left unmitigated.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The vulnerable versions of Traefik are all versions prior to 2.11.35 and 3.6.7. Organizations should ensure they are using patched versions to mitigate this vulnerability.
Mitigation & Remediation
Organizations should upgrade their Traefik installations to version 2.11.35 or 3.6.7 to address this vulnerability. If immediate patching is not possible, consider implementing network controls to limit exposure. Regular monitoring of logs for unusual connection patterns may also help mitigate risks.
For further assistance, organizations may consider engaging in penetration testing services to validate their security posture.
Detection Guidance
Security teams should monitor for log indicators that may suggest exploitation attempts, such as excessive connection requests to ACME TLS endpoints. Behavioral anomalies, such as unexpected spikes in resource usage, can also indicate potential exploitation.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2026-22045 lies in its potential impact on services utilizing Traefik as a load balancer or reverse proxy. Organizations should implement security best practices, such as regular updates and proactive monitoring.
This vulnerability highlights the need for robust resource management in network services. Security teams should learn from this incident to refine their security posture and response strategies.
For further insights, organizations may refer to the following resources: penetration testing methodology and vulnerability management program design to enhance their security frameworks.
In summary, organizations leveraging Traefik must prioritize patching and monitoring to avoid potential service disruptions.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
.webp)