CVE-2026-10774

CVE-2026-10774 is a PSA key slot leak in Zephyr's Bluetooth Mesh implementation that stems from an incomplete refactoring rather than a conventional crypto API misuse. When support for CONFIG_BT_MESH_V1d1 was removed, the corresponding destroy branch was orphaned while the import path remained active, creating a permanently open handle to a PSA key slot that never gets released. The vulnerability only manifests when CONFIG_BT_MESH_PRIV_BEACONS is enabled, which is the default configuration. Every Zephyr Bluetooth Mesh node shipped with default settings is therefore vulnerable. The exhaustion timeline matters: approximately 12 key refresh cycles will exhaust all available PSA key slots, and recovery requires a node reboot — there is no over-the-air remediation. This is not a one-shot crash; it is a persistent degradation condition. Two operational factors accelerate the exhaustion in ways operators may not expect. First, Zephyr's own security guidance recommends periodic key refresh as a best practice. Nodes following this guidance will hit exhaustion faster than those running with stale keys — the security recommendation actively compounds the vulnerability. Second, the persistent nature means a node that exhausts its key slots in the field requires physical access to reboot, not a network command. In smart city, industrial, or healthcare deployments where nodes are mounted in inaccessible locations, this transforms a technical vulnerability into an operational maintenance event. The exploitability constraint is narrow: only a provisioner or network administrator can trigger the teardown paths. This limits the attack to insider threat or compromised credential scenarios rather than arbitrary remote exploitation. However, in shared-infrastructure mesh deployments — multi-tenant smart city networks, managed IoT platforms — a malicious tenant with provisioning authority could degrade nodes belonging to other tenants. The blast radius extends well beyond the individual node: exhausting key slots on routing nodes fragments mesh topology, forcing a full re-provisioning cycle across the entire deployment. Prioritise: verify whether your deployment uses automated key refresh policies. If it does, calculate whether 12 cycles have elapsed since deployment or last reboot. If the deployment environment permits provisioner access to untrusted parties, treat this as a higher-priority remediation. The fix is mechanically straightforward — aligning the destroy guard with CONFIG_BT_MESH_PRIV_BEACONS — but confirm the patch also covers runtime disablement scenarios, not just build-time configuration.

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