Bug 2430198 (CVE-2026-22045)

Summary: CVE-2026-22045 traefik: Traefik: Denial of Service via ACME TLS-ALPN fast path resource exhaustion
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: sdawley
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Traefik, an HTTP reverse proxy and load balancer. This vulnerability exists in the ACME TLS-ALPN fast path, where unauthenticated clients can exploit it. By initiating numerous connections and sending a minimal ClientHello with "acme-tls/1" before ceasing communication, a malicious client can indefinitely tie up system resources such as "go routines" (lightweight threads) and file descriptors. This leads to a Denial of Service (DoS) of the entry point, making the service unavailable to legitimate users.
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Description OSIDB Bzimport 2026-01-15 23:01:37 UTC 
Traefik is an HTTP reverse proxy and load balancer. Prior to 2.11.35 and 3.6.7, there is a potential vulnerability in Traefik ACME TLS certificates' automatic generation: the ACME TLS-ALPN fast path can allow unauthenticated clients to tie up go routines and file descriptors indefinitely when the ACME TLS challenge is enabled. A malicious client can open many connections, send a minimal ClientHello with acme-tls/1, then stop responding, leading to denial of service of the entry point. The vulnerability is fixed in 2.11.35 and 3.6.7.