Istio up to 1.27.7/1.28.4/1.29.0 authorization

Summaryinfo

A vulnerability described as problematic has been identified in Istio up to 1.27.7/1.28.4/1.29.0. This impacts an unknown function. Executing a manipulation can lead to authorization. The identification of this vulnerability is CVE-2026-31838. The attack may be launched remotely. There is no exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability has been found in Istio up to 1.27.7/1.28.4/1.29.0 and classified as problematic. This vulnerability affects an unknown code block. The manipulation with an unknown input leads to a authorization vulnerability. The CWE definition for the vulnerability is CWE-863. The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. This allows attackers to bypass intended access restrictions. As an impact it is known to affect confidentiality. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability was named CVE-2026-31838 since 03/09/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. The technical details are unknown and an exploit is not available.

Upgrading to version 1.27.8, 1.28.5 or 1.29.1 eliminates this vulnerability.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Name

• Istio

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.7
• 1.8
• 1.9
• 1.10
• 1.11
• 1.12
• 1.13
• 1.14
• 1.15
• 1.16
• 1.17
• 1.18
• 1.19
• 1.20
• 1.21
• 1.22
• 1.23
• 1.24
• 1.25
• 1.26
• 1.27
• 1.27.0
• 1.27.1
• 1.27.2
• 1.27.3
• 1.27.4
• 1.27.5
• 1.27.6
• 1.27.7
• 1.28
• 1.28.0
• 1.28.1
• 1.28.2
• 1.28.3
• 1.28.4
• 1.29.0

Website

• Product: https://github.com/istio/istio/

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