CVE-2026-11812 zephyrproject CVE debrief

Who should care

Users and administrators of the affected system should apply the vendor-provided fix to prevent a local actor from triggering a denial of service of the firmware-update path. Additionally, operators, platform administrators, vulnerability management teams, and security teams should be aware of the vulnerability and its potential impact on the system. They should review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance, and plan vendor-supported updates or mitigations through normal change control where exposure is confirmed. Compensating controls for exposed systems should be reviewed while remediation is scheduled and verified. Relevant monitoring, detection, and logs for exposed assets should be checked for extra review. Exceptions, retested remediated assets, and closed items should be tracked, and evidence should be documented before closing the item. The vulnerability management team should also track the affected product deployments in managed environments and assign an owner for follow-up. Security teams should also consider implementing additional security measures, such as restricting access to the update operations to authorized users or roles, and monitoring the system for suspicious activity. Asset inventory and rollback/change windows should also be reviewed to ensure that the vulnerability is properly managed. Source tracking and exposure review should also be performed to ensure that the vulnerability is properly understood and managed. The affected product or component, vulnerability class, likely operational impact, and source-confidence limits should also be reviewed to ensure that the vulnerability is properly understood and managed. The review context should also be considered to ensure that the vulnerability is properly managed. The local actor can invoke update operations and win a timing race against the background handler to trigger a denial of service of the firmware-update path due to corruption of the update subsystem's internal state. The issue is caused by unsynchronized sharing of the ctx structure, allowing two flows to interleave connection setup and teardown, double-closing a

Technical summary

The UpdateHub management subsystem drives every update operation through a single file-scope ctx structure that holds the CoAP block context, payload buffer, status code, socket, and a one-element poll-fd array fds[1]. Access to ctx was not serialized, and prepare_fds() wrote ctx.fds[ctx.nfds] and incremented ctx.nfds with no bounds check. This allows two independent paths to mutate ctx concurrently, leading to corruption of the update subsystem's internal state and denial of service of the firmware-update path.

Defensive priority

Apply the vendor-provided fix, which serializes the entry points with a mutex and adds a bounds check to prepare_fds().

Recommended defensive actions

• Apply the vendor-provided fix, which serializes the entry points with a mutex and adds a bounds check to prepare_fds()
• Restrict access to the update operations to authorized users or roles
• Monitor the system for suspicious activity and implement compensating controls
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Check relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, including its description, CVSS score, and affected products. However, the vendor and product names are not specified. To verify the vulnerability, defenders should check the official CVE Program record and NVD entry for more information. Additionally, defenders should review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance. The vulnerability affects the UpdateHub management subsystem, which drives every update operation through a single file-scope ctx structure. Access to ctx was not serialized, and prepare_fds() wrote ctx.fds[ctx.nfds] and incremented ctx.nfds with no bounds check.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.