Cross-tenant traffic hijacking via backtick rule injection
Published Mar 11, 2026 · Updated Mar 11, 2026
Rule injection in Traefik Labs' Traefik Proxy before 3.6.10 allows remote authenticated users to redirect victim traffic via crafted HTTPRoutes. The Kubernetes Gateway provider's buildHeaderRules and buildQueryParamRules functions interpolate header and query values into backtick-delimited router rules without escaping, allowing injected OR tokens to alter the parsed AST. Exploitation requires HTTPRoute write access and a shared Gateway whose listener hostname constraints isolate tenants; affected requests reach an attacker-controlled backend.
Summary
What happened
Rule injection in Traefik Labs' Traefik Proxy before 3.6.10 allows remote authenticated users to redirect victim traffic via crafted HTTPRoutes. The Kubernetes Gateway provider's buildHeaderRules and buildQueryParamRules functions interpolate header and query values into backtick-delimited router rules without escaping, allowing injected OR tokens to alter the parsed AST. Exploitation requires HTTPRoute write access and a shared Gateway whose listener hostname constraints isolate tenants; affected requests reach an attacker-controlled backend.
The record
- CVE
- CVE-2026-29777
- Published
- Mar 11, 2026
- Updated
- Mar 11, 2026
- Vendor
- Traefik Labs
- Product
- Traefik Proxy
- Classifications
- CWE-74, T1565.002
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Mar 11, 2026CVE publishedPublication date reported by the CVE source.
- Mar 11, 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=< 3.6.10
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
- GHSA integration proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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