Bug 2446342 (CVE-2026-31838) - CVE-2026-31838 istio: Istio: Authorization policy bypass via Envoy RBAC header matching with multiple header values
Summary: CVE-2026-31838 istio: Istio: Authorization policy bypass via Envoy RBAC heade...
Keywords:
Status: NEW
Alias: CVE-2026-31838
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-03-10 23:03 UTC by OSIDB Bzimport
Modified: 2026-03-11 12:27 UTC (History)
19 users (show)

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Description OSIDB Bzimport 2026-03-10 23:03:15 UTC 
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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