CVE-2023-34242: Cilium vulnerable to information leakage via incorrect ReferenceGrant handling

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-06-15 · updated 2026-06-17
Weakness: CWE-200

Description

Cilium is a networking, observability, and security solution with an eBPF-based dataplane. Prior to version 1.13.4, when Gateway API is enabled in Cilium, the absence of a check on the namespace in which a ReferenceGrant is created could result in Cilium unintentionally gaining visibility of secrets (including certificates) and services across namespaces. An attacker on an affected cluster can leverage this issue to use cluster secrets that should not be visible to them, or communicate with services that they should not have access to. Gateway API functionality is disabled by default. This vulnerability is fixed in Cilium release 1.13.4. As a workaround, restrict the creation of `ReferenceGrant` resources to admin users by using Kubernetes RBAC.

Affected products

cilium: before 1.13.4 — fixed in 1.13.4

How to fix

Upgrade to a fixed version: cilium 1.13.4. Check the vendor advisory for mitigations.

References

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