Bug 2452235 (CVE-2026-32695)

Summary: CVE-2026-32695 github.com/traefik/traefik: Traefik: Cross-tenant traffic exposure and host restriction bypass via rule-syntax injection in Knative provider
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
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. When using the Knative provider, Traefik incorrectly interpolates user-controlled values into router rule expressions without proper escaping. This vulnerability allows an attacker to inject malicious rule syntax, leading to a host restriction bypass. In multi-tenant environments, this can result in unauthorized traffic being routed to victim services, potentially exposing cross-tenant traffic.
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Description OSIDB Bzimport 2026-03-27 14:01:32 UTC 
Traefik is an HTTP reverse proxy and load balancer. Prior to versions 3.6.11 and 3.7.0-ea.2, Traefik's Knative provider builds router rules by interpolating user-controlled values into backtick-delimited rule expressions without escaping. In live cluster validation, Knative `rules[].hosts[]` was exploitable for host restriction bypass (for example `tenant.example.com`) || Host(`attacker.com`), producing a router that serves attacker-controlled hosts. Knative `headers[].exact` also allows rule-syntax injection and proves unsafe rule construction. In multi-tenant clusters, this can route unauthorized traffic to victim services and lead to cross-tenant traffic exposure. Versions 3.6.11 and 3.7.0-ea.2 patch the issue.