Skip to content

bt: l2cap le coc: remote oob write via seg counter stored in net_buf user_data

High
ceolin published GHSA-qrcq-hxwj-mqxm Jun 9, 2026

Package

zephyr

Affected versions

<= 4.4.0

Patched versions

None

Description

summary

  • a remote unauthenticated ble peer can trigger a 2-byte out-of-bounds write in the bluetooth host during le coc sdu reassembly when the application enables segmentation (chan_ops.alloc_buf) and the chosen rx pool has user_data_size < 2.
  • observed end effects: (a) asan abort with a backtrace to subsys/bluetooth/host/l2cap.c:2618, and (b) without asan, heap corruption/fatal error in a freelist-poisoning harness.

pins

Patches

main: #104913
v4.3: #108335

For more information

If you have any questions or comments about this advisory:

embargo: 2026-05-21

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Adjacent
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H

CVE ID

CVE-2026-5068

Weaknesses

Out-of-bounds Write

The product writes data past the end, or before the beginning, of the intended buffer. Learn more on MITRE.

Credits