CVE-2026-14373: HashiCorp Nomad Docker Driver Host Namespace Privilege Escalation

Technical summary

CVE-2026-14373 is a privilege escalation vulnerability in HashiCorp Nomad's Docker task driver implementation. The allow_privileged restriction—intended to prevent authenticated job submitters from launching containers with elevated privileges—was not enforced for host namespace mode options. This enforcement gap allows an authenticated attacker to specify Docker run options that bind the container to the host's network, process, or IPC namespace, effectively bypassing container isolation. The vulnerability is rooted in CWE-862 (Missing Authorization), indicating a failure in access control policy enforcement. The attack requires network access and valid Nomad credentials but no user interaction, making it relatively straightforward to exploit once authentication is obtained.

Business impact

This vulnerability directly undermines the security model of multi-tenant or shared Nomad clusters. Organizations relying on Nomad to isolate untrusted or semi-trusted job submitters—such as development teams, CI/CD pipelines, or customers in a platform-as-a-service environment—face data exfiltration and reconnaissance risks. An attacker could extract environment variables, secrets, or application data from the host or sibling containers. For enterprises using Nomad Enterprise with strict workload isolation requirements, this represents a control failure that could violate compliance obligations. The impact scope is cross-cluster (S:C in CVSS), meaning effects extend beyond the vulnerable component.

Affected systems

Nomad Community Edition versions prior to 2.0.4, and Nomad Enterprise versions prior to 2.0.4, 1.11.8, and 1.10.14 are vulnerable. Environments that use the Docker task driver and allow job submissions from authenticated users are at risk. Systems running older branch releases (1.10.x, 1.11.x) require corresponding patches; note the vendor advisory for the specific versions affected in your deployment.

Exploitability

Exploitability is moderate to high. The attack requires valid Nomad credentials (PR:L in CVSS), but once obtained—whether through insider threat, compromised CI/CD accounts, or credential theft—no additional steps, social engineering, or race conditions are needed. The Docker driver's host namespace options are well-documented, making the exploitation method straightforward for an attacker familiar with container orchestration. The vulnerability is not currently tracked in CISA's Known Exploited Vulnerabilities catalog, though public disclosure should prompt rapid awareness in the attacker community.

Remediation

Upgrade immediately to patched versions: Nomad Community Edition 2.0.4 or later, or Nomad Enterprise 2.0.4, 1.11.8, or 1.10.14 (depending on your current version). Before patching, consider restricting job submission permissions to trusted users only, disabling the Docker driver if not essential, or enforcing network policies to limit container-to-host communication. Verify the patch has been applied by confirming version numbers post-deployment; test in a staging cluster first to ensure no configuration regressions.

Patch guidance

Apply the vendor-supplied patches to affected Nomad installations without delay. Nomad Enterprise customers should consult their maintenance schedule and apply the appropriate patch for their licensed version branch (1.10.14, 1.11.8, or 2.0.4). Community Edition users should upgrade to 2.0.4. Perform patching during a maintenance window to avoid job submission interruptions. After patching, audit job configurations submitted during the vulnerability window to identify any containers that may have accessed host namespaces, and revoke or rotate any secrets that were potentially exposed.

Detection guidance

Review Nomad audit logs and job submission history for Docker task driver jobs submitted by authenticated users, particularly those specifying network_mode='host', ipc_mode='host', or pid_mode='host' in the Docker driver config. Monitor for successful submissions that would normally be blocked by policy. If available, enable Nomad's verbose logging for task driver interactions. In runtime detection, monitor for containers with access to host namespaces using container runtime security tools (e.g., Falco, auditd rules), especially containers launched by Nomad clients that expose /proc, /sys, or host network sockets.

Why prioritize this

High CVSS score (7.7) combined with authentication-only requirements and cross-cluster blast radius justifies immediate patching. The vulnerability breaks a fundamental security boundary (container isolation) in shared cluster scenarios. Unlike vulnerabilities requiring complex exploitation chains, this can be weaponized quickly by any authenticated attacker. Organizations using Nomad for multi-tenant workloads or in regulated environments should treat this as critical.

Risk score, explained

The CVSS 3.1 score of 7.7 (HIGH) reflects: network accessibility (AV:N), low attack complexity (AC:L), requirement for low-privilege authentication (PR:L), no user interaction (UI:N), high confidentiality impact (C:H), no integrity or availability impact (I:N, A:N), and changed scope (S:C) affecting other containers and the host. The score does not reach 8.0+ because authentication is required and the attack does not corrupt data or crash systems—it is purely an information disclosure / lateral movement vector. Organizations should not deprioritize based on the score; the missing authorization flaw is severe in shared-tenancy contexts.

Frequently asked questions