CVE-2026-92241
What it is
The AVRCP browsing channel's L2CAP receive-buffer callback, browsing_avrcp_l2cap_alloc_buf() in subsys/bluetooth/host/classic/avrcp.c, allocated from the shared avctp_browsing_rx_pool with K_FOREVER. L2CAP invokes that callback from the Bluetooth RX work queue thread (bt_workq, "BT RX WQ"), both for the head buffer of a new SDU and — through l2cap_br_alloc_frag() and net_buf_append_bytes() — for every further fragment of a reassembled SDU. That same thread is the only context that ever releases these buffers, after bt_l2cap_br_recv_seg() delivers a completed SDU and calls net_buf_unref(), so a wait taken there can never be satisfied. The pool holds CONFIG_BT_MAX_CONN + 1 buffers of CONFIG_BT_AVRCP_BROWSING_L2CAP_MTU bytes (two buffers of 339 bytes in the default configuration). A connected browsing peer can drain it because bt_l2cap_br_recv_seg() in subsys/bluetooth/host/classic/l2cap_br.c accepts the SDU length declared in an SAR_START segment without bounding it by br_chan->rx.mtu: a peer that announces a large SDU and then streams continuation segments forces one pool buffer per segment-worth of data. Once the pool is empty the next allocation blocks forever inside the callback. Triggering the flaw requires a build with CONFIG_BT_CLASSIC and the experimental CONFIG_BT_AVRCP_BROWSING option, an application that registers AVRCP callbacks, and a BR/EDR peer that has established the AVRCP control channel and then the browsing channel, which requires an encrypted (paired) link. No malformed packet is needed — a few hundred bytes of ordinary segmented L2CAP traffic suffice. The consequence is a permanent hang of the whole Bluetooth host, not just of AVRCP: the blocked thread drains bt_dev.rx_queue for all HCI ACL data and low-priority events and also runs the host's internal work items, so all connections stop being serviced and the state is unrecoverable without a reboot. There is no memory-corruption or information-disclosure component. The fix allocates with K_NO_WAIT, so an empty pool now yields a local-busy indication or a channel disconnect that the application can recover from.
At a glance
- Exploitability
- Can be exploited from the same network segment with a low-privilege account. High risk of service disruption.
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- ReservedThe CVE id was reserved by its CNA
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: not scored yet.
- Severity: 5.7 MEDIUM (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Weakness
- CWE-833
- Record status
- Awaiting Analysis
Attack profile CVSS 3.1 · 5.7
- Attack vector
- Adjacent network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Raw vector
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-92241.md and follow it. Check whether this project is affected by CVE-2026-92241. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://github.com/zephyrproject-rtos/zephyr/commit/c8c2438f05165397347613b44dd8e9eaa1243139
- https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-8vpg-4235-9qjj