CVE-2026-5068 bt: l2cap le coc: remote oob write via seg counter stored in net_buf user_data
A remote attacker can cause heap corruption or code execution in Zephyr RTOS via a Bluetooth L2CAP segmentation flaw when specific buffer configurations are used.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-5068?
CVE-2026-5068 is a high-severity memory corruption vulnerability in Zephyrproject Zephyr, published on 9 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
A remote, unauthenticated BLE peer can trigger a 2-byte out-of-bounds write in the Bluetooth host during L2CAP LE CoC SDU reassembly. When the application enables segmentation (via chan_ops.alloc_buf) and the chosen RX pool has a user_data_size smaller than 2 bytes, the segmentation counter stored in the net_buf user_data area is written out of bounds in l2cap_chan_le_recv_seg (subsys/bluetooth/host/l2cap.c). The observed effects are an AddressSanitizer abort and, without ASan, heap corruption / fatal error.
Weakness: CWE-787
Which versions are affected by CVE-2026-5068?
It affects 1 product.
Products include Zephyrproject Zephyr.
How do I fix CVE-2026-5068?
No fix has been published for CVE-2026-5068 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-5068 being exploited?
There is no known exploitation of CVE-2026-5068 in the wild and no public exploit code.
Other vulnerabilities in Zephyrproject Zephyr
- CVE-2026-5067 Out-of-bounds read/write in HTTP WebSocket upgrade via non-null-terminated Sec-WebSocket-Key
- CVE-2022-3806 Bluetooth HCI Error Handling Double Free
- CVE-2017-14199 Memory corruption in getaddrinfo
- CVE-2018-1000800 Null dereference in n/a
- CVE-2021-3329 DOS: Incorrect handling of the initial HCI ACL_MTU handshake packet leads to crash of bluetooth host layer
Sources
Also known as GHSA-qrcq-hxwj-mqxm.