# CVE-2026-99239: linux: In the Linux kernel, the following vulnerability has been resolved:  Bluetooth: L2CAP: refuse __l2cap_chan_add if cha...

CVE-2026-99239 is fixed in linux on 1 platform by DEBIAN-CVE-2026-99239 (version 6.12.115-1), released November 3, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-99239
- Priority: High
- CVSS: 7.8 (high)
- EPSS: 0.0013
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Nov 2, 2026

## Description

In the Linux kernel, the following vulnerability has been resolved:  Bluetooth: L2CAP: refuse __l2cap_chan_add if chan already has conn  l2cap_chan may be linked to l2cap_conn at most once. This is assumed in several places, eg l2cap_chan_del cleanup.  There is a TOCTOU race where the invariant is violated:      [Task 1]                          [Task 2]     l2cap_chan_connect                l2cap_sock_bind       l2cap_chan_lock                   lock_sock       l2cap_state_change                if (sk->sk_state != BT_OPEN)         chan->state = BT_CONNECT         l2cap_sock_state_change_cb      chan->state = BT_BOUND                                         sk->sk_state = BT_BOUND           lock_sock <------------------ release_sock           sk->sk_state = BT_CONNECT  l2cap_sock_connect() does not check sk->sk_state, so since chan->state is now BT_BOUND, subsequent connect() ends up with second __l2cap_chan_add.  Explicitly document and check the invariant in __l2cap_chan_add with WARN_ON_ONCE. The only callsite where it could be hit is l2cap_chan_connect, so add pre-check there to avoid relying on chan->state. chan->state read/write is not properly guarded currently so there can be other TOCTOUC problems.  Add l2cap_lock_chan in l2cap_sock_bind() to guard chan->state write.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 13.5 (trixie) | 6.12.115-1 | [DEBIAN-CVE-2026-99239](https://patchblox.com/security/data/fix/linux/debian-cve-2026-99239.md) | Nov 3, 2026 |

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Data as of 2026-11-08T00:53:09Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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