CVE-2026-31837 PUBLISHED

Istio JWKS resolver to prevent private key material from being exposed when JWKS fetch fails.

Assigner: GitHub_M
Reserved: 09.03.2026 Published: 10.03.2026 Updated: 10.03.2026

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.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
CVSS Score: 8.7

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	High	Confidentiality	None
Attack Complexity	Low	Integrity	None	Integrity	None
Attack Requirements	None	Availability	None	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

Product Status

Vendor	istio
Product	istio
Versions	Version >= 1.29.0-alpha.0, < 1.29.1 is affected Version >= 1.28.0-alpha.0, < 1.28.5 is affected Version < 1.27.8 is affected

References

https://github.com/istio/istio/security/advisories/GHSA-v75c-crr9-733c

Problem Types

CWE-200: Exposure of Sensitive Information to an Unauthorized Actor CWE