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VULNERABILITIES

CVE-2026-31838 Details

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 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.

Metrics

CVSS 3.x Severity and Vector Strings:

NIST: [email protected]CVSS-B:5.3 MEDIUMVector:CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

References to Advisories, Solutions, and Tools

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URLSource(s)Tag(s)
https://github.com/istio/istio/commit/004fd6921314a8e2293fd195d91645dcbbff0aa1 [email protected]
https://github.com/istio/istio/security/advisories/GHSA-974c-2wxh-g4ww [email protected]Vendor Advisory

Weakness Enumeration

CWE-IDCWE NameSource
CWE-863Incorrect Authorization[email protected]

Affected Products

ProductVersions
istio istio
< 1.27.8
>= 1.28.0, < 1.28.5
>= 1.29.0, < 1.29.1

CPE

  • cpe:2.3:a:istio:istio:*:*:*:*:*:*:*:*

Remediation

  • No remediation found in references.

Change History

5 change records found show changes

QUICK INFO

CVE Dictionary Entry:
CVE-2026-31838
NVD Published Date:
Mar 10, 2026
NVD Last Modified:
Jun 17, 2026
Source:
[email protected]
CVE-2026-31838 Details - Not Deferred