High severity · published Jun 9, 2026
CVE-2026-5068
bt: l2cap le coc: remote oob write via seg counter stored in net_buf user_data
8.8
CVSS
0.5%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 39% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
ZE
Zephyr · zephyrproject-rtos
1.14.0 before 4.3.1 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-5068
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-5068
Exploit
https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-qrcq-hxwj-mqxm
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