CVE-2026-10655 zephyrproject CVE debrief

Who should care

Defenders responsible for Zephyr-based systems, particularly those using the asynchronous SNTP client, should assess exposure and prioritize patching for versions 4.2.0, 4.3.0, and 4.4.0. Defenders should prioritize verifying and applying patches for Zephyr versions 4.2.0, 4.3.0, and 4.4.0, as these are known to be affected by this vulnerability. The vulnerability can lead to kernel poll structure corruption, potentially allowing attackers to execute

Why it matters

A use-after-free race condition in the Zephyr asynchronous SNTP client can lead to kernel poll structure corruption, potentially allowing attackers to execute arbitrary code or cause a denial-of-service.

• Verify and apply patches to prevent potential use-after-free exploits
• Review and update configurations to ensure proper synchronization
• Monitor for potential exploitation attempts

Technical summary

The asynchronous SNTP client in Zephyr closed the UDP socket file descriptor directly from the calling thread immediately after detaching it from the network socket service, without synchronizing with the socket-service poll thread. This can result in a use-after-free / object confusion of kernel poll structures. The vulnerability is caused by the SNTP client closing the UDP socket file descriptor directly from the calling thread immediately after detaching it from the network socket service, without synchronizing with the socket-service poll thread. This issue can lead to a use-after-free / object confusion of kernel poll structures, potentially allowing attackers to execute arbitrary code or cause a denial-of

Defensive priority

Defenders should prioritize verifying and applying patches for Zephyr versions 4.2.0, 4.3.0, and 4.4.0, as these are known to be affected by this vulnerability.

Recommended defensive actions

• Verify and apply patches for Zephyr versions 4.2.0, 4.3.0, and 4.4.0
• Review and update Zephyr configurations to ensure the socket service is properly synchronized
• Monitor for potential exploitation attempts
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and source item provide details on the vulnerability, including its description, affected versions, and references to patches and advisories. The asynchronous SNTP client in Zephyr closed the UDP socket file descriptor directly from the calling thread immediately after detaching it from the network socket service, without synchronizing with the socket-service poll thread. This issue can lead to a use-after-free / object confusion of kernel poll structures. The SNTP timeout path is the normal no-response failure mode, so

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.