What’s Vulnerable › Vulnerabilities

CVE-2026-31837: Istio JWKS resolver to prevent private key material from being exposed when JWKS fetch fails.

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-03-10 · updated 2026-07-20
• Weakness: CWE-200

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 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: before 1.27.8; from 1.28.0 before 1.28.5; from 1.29.0 before 1.29.1 — fixed in 1.27.8, 1.28.5, 1.29.1

How to fix

Upgrade to a fixed version: istio 1.27.8, 1.28.5, 1.29.1. Check the vendor advisory for mitigations.

References

• https://github.com/istio/istio/security/advisories/GHSA-v75c-crr9-733c
• https://access.redhat.com/errata/RHSA-2026:10184
• https://access.redhat.com/errata/RHSA-2026:5948
• https://access.redhat.com/errata/RHSA-2026:5950
• https://access.redhat.com/errata/RHSA-2026:5952
• https://access.redhat.com/security/cve/CVE-2026-31837
• https://bugzilla.redhat.com/show_bug.cgi?id=2446344
• https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-31837.json

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