CVE-2026-31837: Istio

High severity, CVSS 7.5. EPSS: 0.7% chance of exploitation in the next 30 days.

Istio is an open platform to connect, manage, and secure microservices. Prior to 1.29.1, 1.28.5, and 1.27.8, a user of Istio is impacted if the JWKS resolver becomes unavailable or the fetch fails, exposing hardcoded defaults regardless of use of the RequestAuthentication resource. This vulnerability is fixed in 1.29.1, 1.28.5, and 1.27.8.

Affected products

• Istio Istio: before 1.27.8 (fixed in 1.27.8); from 1.28.0, before 1.28.5 (fixed in 1.28.5); from 1.29.0, before 1.29.1 (fixed in 1.29.1)

Published 2026-03-10. Last modified 2026-07-20.