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The vulnerability tracked as CVE-2026-77459 affects Argo CD, a declarative GitOps continuous delivery tool for Kubernetes environments. During standard synchronization operations, Argo CD validates application manifests against configured AppProject constraints, which include target destination namespaces, servers, and allowed or denied resource types. However, resource hooks configured for execution during deletion phases—specifically PreDelete and PostDelete hooks—completely bypass these vital authorization and validation checks. When an application is deleted from the cluster, the application-controller provisions these hooks using elevated controller credentials without verifying whether the target namespace or cluster-scoped resource is permitted by the corresponding AppProject. Consequently, an attacker or unauthorized user with write access to a connected Git repository can commit malicious hook manifests specifying restricted API groups, kinds, or cluster-scoped objects such as ClusterRoleBindings. When the application lifecycle reaches the deletion stage, the controller executes the payload, granting attackers the ability to escalate privileges, escape project boundaries, or manipulate unauthorized namespaces across the destination cluster.
DailyCVE Form:
Platform: Argo CD
Version: v2.10.0-v3.6.0-rc2
Vulnerability : Authorization Bypass
Severity: Critical
date: October 7, 2026
Prediction: Released
What Undercode Say
Bash Commands and Codes
Check affected Argo CD version argocd version --client Inspect application manifests for hooks grep -rn "argocd.argoproj.io/hook" ./manifests/
Exploit: (Educational Purposes!)
An attacker commits a resource hook into the backing Git repository with a PreDelete or PostDelete annotation targeting a restricted cluster-scoped resource or unauthorized namespace. Because the application-controller skips AppProject validations upon application deletion, it applies the manifest using high privileges, resulting in unauthorized resource creation.
Protection
Upgrade to Argo CD versions 3.3.15, 3.4.10, 3.5.4, 3.6.0-rc2 or newer. Restrict write access to Git repositories and limit application deletion privileges to trusted personnel.
Impact
Attackers can create unauthorized cluster-scoped objects or deploy resources into restricted namespaces, leading to full cluster compromise or privilege escalation.
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Sources:
Reported By: github.com
Extra Source Hub:
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