A flaw was found in ArgoCD Image Updater. This vulnerability allows an attacker, with permissions to create or modify an ImageUpdater resource in a multi-tenant environment, to bypass namespace boundaries. By exploiting insufficient validation, the attacker can trigger unauthorized image updates on applications managed by other tenants. This leads to cross-namespace privilege escalation, impacting application integrity through unauthorized application updates.
The vulnerability results from insufficient validation of ImageUpdater resources (CWE-1220 — Insufficient Granularity of Access Control). An attacker with permissions to create or modify such resources in their own namespace can construct a malicious resource that triggers image updates in namespaces of other tenants. The isolation mechanism between tenants is not enforced sufficiently, allowing privilege escalation beyond the assigned scope of permissions. As a result, the attacker gains the ability to influence the lifecycle of applications managed by other cluster users.
An attacker can force unauthorized updates of container images in applications of other tenants, compromising the integrity of those applications and potentially injecting a malicious image into the production environment. This is a cross-namespace privilege escalation affecting the confidentiality, integrity, and availability of applications sharing a cluster.
Patches available from the vendor should be applied according to references (Red Hat: https://access.redhat.com/security/cve/CVE-2026-6388). Until the fix is applied, it is recommended to restrict permissions to create and modify ImageUpdater resources only to trusted users and to monitor unexpected image updates in the cluster environment.
ArgoCD Image Updater deployed in multi-tenant environments — versions indicated in vendor references
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:H/A:L