CVE-2026-31838: exploitation status and patch state
CVE-2026-31838 · CVSS 5.3 MEDIUM · EPSS <1%
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.
Is CVE-2026-31838 exploited?
Not in the CISA KEV catalog.
EPSS puts exploitation in the next 30 days at <1%.
Public exploit code: none found in monitored sources.