Medium
Traefik Kubernetes CRD allows unauthorized cross-namespace middleware binding
Type: advisorySources: OSV
Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.43, 3.6.14, and 3.7.0-rc.2, there is a potential vulnerability in Traefik's Kubernetes CRD provider cross-namespace isolation enforcement. When providers.kubernetesCRD.allowCrossNamespace=false, Traefik correctly rejects direct cross-namespace middleware references from IngressRoute objects, but fails to apply the same restriction to middleware references nested inside a Chain middleware's spec.chain.middlewares[]. An actor with permission to create or update Traefik CRDs in their own namespace can exploit this to cause Traefik to resolve and apply middleware objects from another namespace, bypassing the documented isolation boundary. This issue has been patched in versions 2.11.43, 3.6.14, and 3.7.0-rc.2.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-41174
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 7 Nov 2026, 01:15 UTC · Revision 1
Source evidence
Traefik Kubernetes CRD allows unauthorized cross-namespace middleware binding
core-osv · Original sourcePublished 30 Apr 2026, 20:20 UTC
Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.43, 3.6.14, and 3.7.0-rc.2, there is a potential vulnerability in Traefik's Kubernetes CRD provider cross-namespace isolation enforcement. When providers.kubernetesCRD.allowCrossNamespace=false, Traefik correctly rejects direct cross-namespace middleware references from IngressRoute objects, but fails to apply the same restriction to middleware references nested inside a Chain middleware's spec.chain.middlewares[]. An actor with permission to create or update Traefik CRDs in their own namespace can exploit this to cause Traefik to resolve and apply middleware objects from another namespace, bypassing the documented isolation boundary. This issue has been patched in versions 2.11.43, 3.6.14, and 3.7.0-rc.2.
osv:CVE-2026-41174
Complete source record
{
"id": "10c24382b3e86d95b948e299f170d98e3f0ef93e14f46b1d9345598771976a09",
"url": "https://osv.dev/vulnerability/CVE-2026-41174",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "Traefik Kubernetes CRD allows unauthorized cross-namespace middleware binding",
"summary": "Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.43, 3.6.14, and 3.7.0-rc.2, there is a potential vulnerability in Traefik's Kubernetes CRD provider cross-namespace isolation enforcement. When providers.kubernetesCRD.allowCrossNamespace=false, Traefik correctly rejects direct cross-namespace middleware references from IngressRoute objects, but fails to apply the same restriction to middleware references nested inside a Chain middleware's spec.chain.middlewares[]. An actor with permission to create or update Traefik CRDs in their own namespace can exploit this to cause Traefik to resolve and apply middleware objects from another namespace, bypassing the documented isolation boundary. This issue has been patched in versions 2.11.43, 3.6.14, and 3.7.0-rc.2.",
"evidence": "osv:CVE-2026-41174",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2026-41174",
"aliases": [
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"GHSA-xhjw-95fp-8vgq",
"GO-2026-5760"
],
"metrics": [
{
"type": "CVSS_V4",
"score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N"
}
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"source": "REFERENCES_TAG",
"original_tag": "v2.11.43"
},
{
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"source": "REFERENCES_TAG",
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"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-41174.json"
}
}
],
"modified": "2026-10-28T02:30:48.746565806Z",
"provider": "osv",
"references": [
"https://github.com/traefik/traefik/releases/tag/v2.11.43",
"https://github.com/traefik/traefik/releases/tag/v3.6.14",
"https://github.com/traefik/traefik/releases/tag/v3.7.0-rc.2",
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/41xxx/CVE-2026-41174.json",
"https://github.com/traefik/traefik/security/advisories/GHSA-xhjw-95fp-8vgq",
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"https://github.com/traefik/traefik/commit/df00d82fc7f12e07199551832b54de6d0e55414d"
],
"provider_metadata": {
"cwe_ids": [
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"CWE-863"
],
"cna_assigner": "GitHub_M",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/41xxx/CVE-2026-41174.json"
}
},
"related_cves": [
{
"value": "CVE-2026-41174",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 516903,
"published_at": "2026-04-30T20:20:29.679+00:00"
}