Credential disclosure via unchecked cross-provider middleware reference
Published Sep 4, 2026 · Updated Sep 4, 2026
Authorization bypass in Traefik Proxy 3.7.1 through 3.7.12 allows remote authenticated users to disclose backend credentials. The Kubernetes Ingress loadService path copies the service.middlewares annotation into the dynamic service without checking its namespace against crossProviderNamespaces. Exploitation requires namespace-level Kubernetes privileges, a known operator middleware that injects credentials, and a tenant-controlled backend that receives them.
Summary
What happened
Authorization bypass in Traefik Proxy 3.7.1 through 3.7.12 allows remote authenticated users to disclose backend credentials. The Kubernetes Ingress loadService path copies the service.middlewares annotation into the dynamic service without checking its namespace against crossProviderNamespaces. Exploitation requires namespace-level Kubernetes privileges, a known operator middleware that injects credentials, and a tenant-controlled backend that receives them.
The record
- CVE
- CVE-2026-85594
- Published
- Sep 4, 2026
- Updated
- Sep 4, 2026
- Vendor
- Traefik Labs
- Product
- Traefik Proxy
- Classifications
- CWE-639, T1552
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Sep 4, 2026CVE publishedPublication date reported by the CVE source.
- Sep 4, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=3.7.1 <=3.7.12
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
- Traefik service middleware proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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