CVE-2026-31838

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.

CVSS v3 5.3 MEDIUM

5.3^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 3.9 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact LOW

Integrity Impact NONE

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/istio/istio/security/advisories/GHSA-974c-2wxh-g4ww	Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:istio:istio::::::::
	cpe:2.3:a:istio:istio::::::::
	cpe:2.3:a:istio:istio::::::::

History

No history.

Information

Published : 2026-03-10 22:16

Updated : 2026-03-18 18:58

NVD link : CVE-2026-31838

Mitre link : CVE-2026-31838

CVE.ORG link : CVE-2026-31838

JSON object : View

Products Affected

istio

istio

CWE

CWE-863

Incorrect Authorization

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