PT-2026-28442 · Containous · Traefik
Nmengin
·
Published
2026-03-27
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Updated
2026-04-07
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CVE-2026-32695
CVSS v3.1
7.7
High
| Vector | AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N |
Name of the Vulnerable Software and Affected Versions
Traefik versions prior to 3.6.11 and 3.7.0-ea.2
Description
Traefik’s Knative provider constructs router rules by incorporating user-provided values into rule expressions without proper sanitization. Specifically, the
rules[].hosts[] field in Knative configurations is susceptible to host restriction bypass, allowing an attacker to inject malicious host entries (e.g., tenant.example.com) || Host(attacker.com) and serve attacker-controlled hosts. The headers[].exact field also permits rule-syntax injection, leading to unsafe rule construction. This issue poses a significant risk in multi-tenant clusters, potentially enabling unauthorized traffic routing to victim services and exposing cross-tenant traffic. The vulnerability stems from the use of fmt.Sprintf with backtick-delimited literals, which allows malicious input containing backticks to terminate literals and inject additional operators into Traefik’s rule language. A proof-of-concept (PoC) demonstrates the injection of host and header rules, bypassing intended routing restrictions.Recommendations
Upgrade to Traefik version 3.6.11 or 3.7.0-ea.2 to address this issue.
Exploit
Fix
Special Elements Injection
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Weakness Enumeration
Related Identifiers
Affected Products
Traefik