https://feed.craftedsignal.io/vendors/argo/Trending threats, MITRE ATT&CK coverage, and detection metadata — refreshed continuously.Hugoenhello@craftedsignal.iohello@craftedsignal.ioMon, 04 May 2026 20:11:38 +0000https://feed.craftedsignal.io/briefs/2026-05-argo-workflow-bypass/Mon, 04 May 2026 20:11:38 +0000hello@craftedsignal.iohttps://feed.craftedsignal.io/briefs/2026-05-argo-workflow-bypass/Argo Workflows has an incomplete fix for CVE-2026-31892, allowing bypass of templateReferencing restrictions to modify pod specifications, leading to potential privilege escalation and security context overrides.Argo Workflows, a Kubernetes-native workflow engine, contains an incomplete fix for CVE-2026-31892. The initial patch blocked podSpecPatch modifications when templateReferencing: Strict was active. However, other fields within the WorkflowSpec that influence pod creation, such as hostNetwork, serviceAccountName, and securityContext, were not restricted. This allows a malicious user to bypass intended security controls and potentially escalate privileges within the Kubernetes cluster. Versions affected include those supporting the templateReferencing feature, specifically v4.0.2 and v3.7.11, which include the initial fix for CVE-2026-31892 but are still vulnerable to this bypass. This vulnerability exists because the check in setExecWorkflow only validates HasPodSpecPatch(), while other critical fields are applied directly to the pod specification. The bypass affects both Strict and Secure modes.

Attack Chain

1. Attacker gains create Workflow permission within the Argo Workflows environment.
2. Attacker crafts a Workflow manifest that references a hardened WorkflowTemplate.
3. Attacker sets hostNetwork: true (or other vulnerable fields like securityContext, serviceAccountName, tolerations, or automountServiceAccountToken) in the Workflow manifest.
4. The Workflow is submitted, and the setExecWorkflow function in the Argo controller only checks for podSpecPatch.
5. Due to the missing validation, the user-defined hostNetwork: true (or other vulnerable fields) is merged with the WorkflowTemplate specification.
6. The createWorkflowPod function reads the merged specification and applies the hostNetwork: true setting directly to the pod specification, bypassing the intended restrictions.
7. A pod is created with host networking enabled, granting the container access to the host’s network namespace.
8. The attacker can now access sensitive information or perform actions on the network as if they were running directly on the host.

Impact

Successful exploitation allows an attacker to bypass the intended security restrictions imposed by Argo Workflows’ templateReferencing feature. This can lead to privilege escalation, unauthorized access to network resources, and the potential to compromise other containers or nodes within the Kubernetes cluster. The impact is most significant in clusters that rely on Argo’s Strict mode as the primary enforcement layer, as other Kubernetes-level controls like PodSecurity admission or OPA/Gatekeeper may not be in place to mitigate these bypasses.

Recommendation

• Deploy the Sigma rule Argo Workflow Host Network Bypass to detect workflows attempting to set hostNetwork: true, and tune for your environment.
• Deploy the Sigma rule Argo Workflow Service Account Override to detect workflows attempting to override the service account.
• Upgrade to a patched version of Argo Workflows that addresses CVE-2026-42296, ensuring that all WorkflowSpec fields that influence pod security posture are validated.
• Implement Kubernetes-level controls, such as PodSecurity admission or OPA/Gatekeeper, to provide an additional layer of defense against unauthorized pod specification modifications.

]]>highadvisoryargo-workflowskubernetesprivilege-escalationdefense-evasionhttps://feed.craftedsignal.io/briefs/2024-05-argo-configmap-auth-bypass/Fri, 03 May 2024 16:23:00 +0000hello@craftedsignal.iohttps://feed.craftedsignal.io/briefs/2024-05-argo-configmap-auth-bypass/The Sync Service's ConfigMap-backed provider in Argo Workflows performs zero authorization checks on all CRUD operations, allowing any authenticated user to create, read, update, and delete Kubernetes ConfigMaps containing synchronization limits, potentially leading to denial of service, workflow disruption, information disclosure, or arbitrary ConfigMap manipulation in Argo Workflows versions v4.0.0 to v4.0.4.Argo Workflows, a Kubernetes-native workflow engine, is vulnerable to an authorization bypass in its Sync Service’s ConfigMap-backed provider. This vulnerability, present in versions 4.0.0 through 4.0.4, stems from a lack of authorization checks on CRUD operations performed on ConfigMaps. This means that any authenticated user, even with a fake Bearer token, can create, read, update, and delete Kubernetes ConfigMaps used for synchronization limits. This flaw allows attackers to potentially disrupt workflow execution, access sensitive configuration data, or even manipulate ConfigMaps in namespaces accessible to the server’s service account. The vulnerability was reported on May 4, 2026, and poses a significant risk to Argo Workflows deployments.

Attack Chain

1. Attacker gains network access to the Argo Server.
2. Attacker authenticates to the Argo Server using any valid or even a “fake” Bearer token (e.g., fake-token).
3. Attacker crafts a POST request to the /api/v1/sync/default endpoint to create a new Sync Limit ConfigMap with specified parameters like namespace, ConfigMap name, key, and limit.
4. The Argo Server’s configMapSyncProvider.createSyncLimit function executes without performing any authorization checks.
5. The function uses the Kubernetes client to create a ConfigMap in the specified namespace based on the attacker’s input.
6. Attacker can subsequently send GET, PUT, or DELETE requests to /api/v1/sync/default/{key} to read, update, or delete existing Sync Limit ConfigMaps without authorization.
7. The Argo Server processes these requests, modifying the ConfigMaps accordingly, due to the missing auth.CanI checks.
8. The attacker disrupts workflow execution, gains access to sensitive configuration data, or manipulates ConfigMaps, leading to denial of service or other malicious outcomes.

Impact

Successful exploitation of this vulnerability allows an attacker with network access to the Argo Server and valid or fake authentication credentials to perform several malicious actions. They can cause a denial of service by setting sync limits to zero or a very low number, effectively blocking parallel workflow execution. Attackers can also disrupt running workflows by modifying existing sync limits. Furthermore, they can gain access to sensitive information by reading ConfigMap data or manipulate ConfigMaps in any namespace accessible to the server’s service account. This could lead to complete compromise of the Argo Workflows environment.

Recommendation

• Upgrade to Argo Workflows version 4.0.5 or later to patch CVE-2026-42297 and mitigate the missing authorization checks.
• Monitor access logs on the Argo Server for unexpected API calls to the /api/v1/sync endpoints, especially POST, PUT, and DELETE requests, which could indicate unauthorized ConfigMap manipulation. Use the rule Argo Workflows ConfigMap Sync Service Modification to detect unauthorized modifications.
• Implement network segmentation and access controls to limit network access to the Argo Server, reducing the attack surface.

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