# CVE-2026-19940: Zephyr RTOS Bluetooth HFP AG work queue memory corruption

Source: https://junglewise.ai/threats/cve-2026-19940-the-bluetooth-classic-hands-free-profile-audio-gateway  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-13. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-19940 · Severity: medium · CVSS 6.5 · Published 2026-10-13

The Bluetooth Hands-Free Profile Audio Gateway implementation in Zephyr RTOS contains a memory corruption vulnerability in its work queue management. An attacker within Bluetooth range can trigger a system crash or hang by repeatedly connecting and disconnecting a Hands-Free device on the same ACL link, exploiting a race condition in the connection pool reuse logic.

Technologies: [Zephyr Project Zephyr RTOS](https://junglewise.ai/threats/technologies/zephyr). Vendors: [Zephyr Project](https://junglewise.ai/threats/vendors/zephyr-project).

## Quick answers

**Is CVE-2026-19940 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-19940 being exploited in the wild.

**How severe is CVE-2026-19940?** Medium severity, with a CVSS score of 6.5, published 13 October 2026.

**Which products and versions are affected?** Zephyr Project Zephyr RTOS Versions with CONFIG_BT_HFP_AG enabled.

**Is there a fix for CVE-2026-19940?** No fixed version is recorded yet. Disable CONFIG_BT_HFP_AG unless the Hands-Free Profile Audio Gateway role is required, or do not implement the asynchronous get_ongoing_call callback to avoid scheduling the vulnerable work structure.</anigation>
</invoke> If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-19940 attacked?** It is attacked from the adjacent network, in an operating system.

**Am I affected by CVE-2026-19940?** Check whether you run Zephyr Project Zephyr RTOS at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix


Disable CONFIG_BT_HFP_AG unless the Hands-Free Profile Audio Gateway role is required, or do not implement the asynchronous get_ongoing_call callback to avoid scheduling the vulnerable work structure.</anigation>
</invoke>

## Technical details

The vulnerability occurs in subsys/bluetooth/host/classic/hfp_ag.c where disconnection fails to cancel pending ag->ongoing_call_work before the connection pool slot is marked free and reused. When a new connection reuses the same slot, hfp_ag_create() zeroes and re-initializes the work structure while the kernel's timeout list still references it, corrupting the timeout list's internal links. A remote peer can deterministically trigger this by sending AT+CIND?, disconnecting the RFCOMM DLC, and immediately reconnecting on the same ACL link before the timeout expires, causing NULL pointer dereferences or list cycles in the kernel's clock announcement path.

## Affected products

- Zephyr Project Zephyr RTOS Versions with CONFIG_BT_HFP_AG enabled

## Timeline

- 2026-10-13: disclosed

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