PatchSiren cyber security CVE debrief

CVE-2026-5068 zephyrproject-rtos CVE debrief

CVE-2026-5068 is a HIGH severity vulnerability with a CVSS score of 7.6. A remote, unauthenticated BLE peer can trigger a 2-byte out-of-bounds write in the Bluetooth host during L2CAP LE CoC SDU reassembly. This occurs when the application enables segmentation and the chosen RX pool has a user_data_size smaller than 2 bytes. The observed effects are an AddressSanitizer abort and, without ASan, heap corruption / fatal error.

Vendor: zephyrproject-rtos
Product: Zephyr
CVSS: HIGH 7.6
CISA KEV: Not listed in stored evidence
Original CVE published: 2026-06-09
Original CVE updated: 2026-06-09
Advisory published: 2026-06-09
Advisory updated: 2026-06-09

Who should care

Users of Bluetooth host applications that enable segmentation and have a chosen RX pool with a user_data_size smaller than 2 bytes should be aware of this vulnerability.

Technical summary

The vulnerability is caused by an out-of-bounds write in the l2cap_chan_le_recv_seg function (subsys/bluetooth/host/l2cap.c).

Defensive priority

HIGH

Recommended defensive actions

Apply patches or updates from the vendor as soon as they are available.
Review and update application configurations to prevent exploitation.

Evidence notes

The CVE was published on 2026-06-09T08:16:29.073Z and modified on 2026-06-09T13:53:24.200Z.

Official resources

CVE-2026-5068 was disclosed by [email protected].