CVE-2026-31838

5.3 MEDIUM
Published: March 10, 2026 Modified: March 18, 2026
View on NVD

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.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
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

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/istio/istio/security/advisories/GHSA-974c-2wxh-g4ww
Source: security-advisories@github.com
Vendor Advisory

1 reference(s) from NVD

Quick Stats

CVSS v3 Score
5.3 / 10.0
EPSS (Exploit Probability)
0.0%
11th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

istio