CVE-2026-19186 zephyrproject CVE debrief

Who should care

Defenders of Zephyr-based systems, particularly those using IEEE 802.15.4 frame decryption, should assess exposure and verify the affected versions of the Zephyr product. They should also review and apply patches, implement compensating controls, and monitor for potential exploitation. Additionally, defenders should confirm whether affected product deployments exist in managed environments, plan vendor-supported updates or mitigations, and track exceptions

Why it matters

The integer underflow vulnerability in IEEE 802.15.4 frame decryption leads to out-of-bounds read and write operations, allowing for potential data corruption or crashes. Defenders of Zephyr-based systems should assess exposure, verify affected versions, and apply patches to prevent exploitation.

• Verification of affected versions and patch application is required to prevent exploitation
• Out-of-bounds read and write operations can lead to data corruption or crashes
• Exploitation can occur through a single crafted short frame from any device in radio range

Technical summary

The ieee802154_decipher_data_frame() function in subsys/net/l2/ieee802154/ieee802154_frame.c does not check if the received frame is at least ll_hdr_len + authtag_len bytes long before computing the payload length. This leads to an integer underflow, which causes the crypto layer to read and write several hundred bytes past the end of the packet buffer. The vulnerability affects Zephyr-based systems using IEEE 802.15.4 frame decryption. The issue can be mitigated by reviewing and applying the patch provided by the vendor, verifying affected versions, and implementing compensating controls.

Defensive priority

High

Recommended defensive actions

• Review and apply the patch provided by the vendor
• Verify the affected versions of the Zephyr product
• Implement compensating controls to detect and prevent exploitation
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• 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
• Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The CVE record and source item provide details on the integer underflow vulnerability in IEEE 802.15.4 frame decryption, which leads to out-of-bounds read and write. The vulnerability is caused by the lack of checking for the received frame length before computing the payload length.

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.