CVE-2026-18418 zephyrproject CVE debrief

Who should care

Defenders responsible for the firmware and logging configurations of peer domains, especially those with control over the same SoC, should assess exposure and prioritize verification and remediation efforts.

Why it matters

CVE-2026-18418 is a low-severity vulnerability in the zbus proxy agent IPC backend that can be triggered by a peer domain, potentially leading to an out-of-bounds read. Defenders should prioritize verifying peer domain firmware and logging configurations.

• Defenders need to verify peer domain firmware to prevent exploitation.
• Logging configurations must be reviewed to avoid triggering the out-of-bounds read.
• Remediation priority is medium, as a fix commit is available.
• Exploitation requires control over the firmware of a peer domain.

Technical summary

The zbus proxy agent IPC backend in subsys/zbus/proxy_agent/zbus_proxy_agent_ipc.c logs the channel name of a rejected inter-domain frame with a plain %s conversion. The frame type struct zbus_proxy_msg carries a fixed-size channel_name[] array as its last member, and nothing in the transport guarantees the array is NUL-terminated. This can cause an out-of-bounds read when the channel name is logged. A peer domain can trigger this by sending a frame with an out-of-range message_size or a channel_name[] without a NUL byte. The issue requires CONFIG_ZBUS_PROXY_AGENT_IPC and logging at warning level or above. Defenders should prioritize verifying peer domain firmware and logging configurations.

Defensive priority

Defenders should prioritize verifying the firmware of peer domains, especially those with control over the same SoC, and ensure logging configurations are set to prevent triggering this issue.

Recommended defensive actions

• Verify the firmware of peer domains, especially those with control over the same SoC.
• Ensure logging configurations are set to prevent triggering this issue.
• Review and apply the fix commit (fc065f79a568a6c6cc14b89795bd60e5eabd6f02) for affected versions (prior to 4.4.2).
• Monitor for and respond to 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.

Evidence notes

The CVE record and source item provide details about the vulnerability, including its description, CVSS score, and affected versions. However, the corpus does not establish versions beyond 4.4.0 and 4.4.2, exploitation, or remediation beyond a fix commit and advisory.

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.