CVE-2026-31838
Description
Istio is an open platform to connect, manage, and secure microservices. Prior to 1.29.1, 1.28.5, and 1.27.8, a vulnerability in Envoy RBAC header matching could allow authorization policy bypass when policies rely on HTTP headers that may contain multiple values. An attacker could craft requests with multiple header values in a way that causes Envoy to evaluate the header differently than intended, potentially bypassing authorization checks. This may allow unauthorized requests to reach protected services when policies depend on such header-based matching conditions. This vulnerability is fixed in 1.29.1, 1.28.5, and 1.27.8.
How to fix
- istio istio1.27.8, 1.28.5, 1.29.1 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| istio istio | v < 1.27.8, 1.28.0 ≤ v < 1.28.5, 1.29.0 ≤ v < 1.29.1 | 1.27.8, 1.28.5, 1.29.1 |
Check your version
Choose the product and enter the version you run to see whether it falls in the affected range.
Attack Surface Management
See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.