CVE-2026-14896: HashiCorp Nomad Cross-Namespace Authorization Bypass in Dynamic Host Volumes

Technical summary

The vulnerability stems from insufficient authorization checks in the dynamic host volumes feature of Nomad. An authenticated operator possessing the host_volume:delete permission within one namespace can exploit a gap in permission validation to delete sticky volume claims associated with jobs running in other namespaces. The flaw violates the namespace boundary enforcement expected in a multi-tenant orchestration platform. The CVSS 3.1 score of 4.2 reflects the requirement for authenticated access and the need for specific operator permissions, but acknowledges integrity and availability impact through unauthorized volume deletion.

Business impact

In multi-tenant Nomad deployments, this vulnerability allows cross-namespace resource interference. A malicious or compromised operator account can disrupt workloads in other teams' namespaces by deleting volume claims, leading to job failures, data loss, and operational disruption. Organizations relying on namespace-based isolation for regulatory compliance, cost allocation, or team separation face weakened security boundaries. Affected platforms may experience unexpected job terminations and require incident response to determine the scope of unauthorized deletions.

Affected systems

HashiCorp Nomad Community Edition versions prior to 2.0.4 are vulnerable. HashiCorp Nomad Enterprise is affected in versions prior to 2.0.4, 1.11.8, and 1.10.14. The vulnerability specifically impacts deployments using the dynamic host volumes feature with multi-namespace configurations.

Exploitability

Exploitation requires valid operator credentials with host_volume:delete permission. No elevated privileges, network connectivity tricks, or user interaction are needed beyond the initial authenticated session. However, an attacker must have legitimate Nomad access and know of jobs and volume claims in target namespaces, which somewhat limits opportunistic exploitation. The medium CVSS score reflects this authentication requirement and the conditional nature of the attack vector.

Remediation

Upgrade Nomad to patched versions: Community Edition 2.0.4 or later, or Enterprise Edition 2.0.4, 1.11.8, or 1.10.14 depending on your deployed branch. Organizations unable to patch immediately should restrict host_volume:delete permissions to trusted operators and implement access control reviews to minimize blast radius. Namespace isolation should be treated as a logical boundary, not a security boundary, until patches are applied.

Patch guidance

Apply the following patched versions immediately: Nomad Community Edition 2.0.4+, Nomad Enterprise 2.0.4, 1.11.8, or 1.10.14. Plan upgrades during maintenance windows, testing in a staging environment first. For organizations on long-term support branches, verify availability of patches against the vendor advisory. The authorization fix requires no configuration changes post-upgrade.

Detection guidance

Monitor Nomad audit logs for host_volume delete operations, particularly those initiated by operators and cross-referenced against the invoking namespace and target job namespace. Alert on delete events where the operator's primary namespace differs from the job's namespace. Review recent volume claim deletions and correlate with operator activity. Audit ACL policies to identify operators with unnecessary host_volume:delete permissions across namespaces.

Why prioritize this

Although the CVSS score is medium (4.2), organizations with multi-namespace Nomad deployments used for organizational or team isolation should prioritize patching. The vulnerability directly exploits architectural trust assumptions—namespace boundaries—making it a higher-priority concern for those relying on namespaces for compliance or multi-tenancy. Single-namespace deployments face lower risk.

Risk score, explained

The CVSS 3.1 score of 4.2 (MEDIUM) appropriately captures the requirement for authenticated access (PR:L) and challenging conditions (AC:H), offset by integrity and availability impacts (I:L, A:L). The score does not reflect organizational context; teams using strong RBAC and namespace separation may assign higher internal risk ratings.

Frequently asked questions