CVE-2026-53256 is a vulnerability in Linux Kernel
Published on June 25, 2026
Bluetooth: RFCOMM: hold listener socket in rfcomm_connect_ind()
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().
Products Associated with CVE-2026-53256
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Affected Versions
Linux:- Version 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and below f5ec76bdbeb80f75ad0be204371afffee0f8fac8 is affected.
- Version 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and below a07d741c077d4e34b16458241a94d29039386553 is affected.
- Version 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and below 1f73f92f66251065a5f39b09a47cf05ea14d3107 is affected.
- Version 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and below de31973ef00e5aa55496f84cf6a44bb157a34e02 is affected.
- Version 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and below b0e33e409715c617e2a20f46f99aa5403a14dfda is affected.
- Version 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and below 8802413ce63175fb522a2bd609fb043a3550c720 is affected.
- Version 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and below 6f4462d12133106460d7c046b95aad2491e3fddf is affected.
- Version 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and below 43c441edacf953b39517a44f5e5e10a93618b226 is affected.
- Version 2.6.12 is affected.
- Before 2.6.12 is unaffected.
- Version 5.10.259, <= 5.10.* is unaffected.
- Version 5.15.210, <= 5.15.* is unaffected.
- Version 6.1.176, <= 6.1.* is unaffected.
- Version 6.6.143, <= 6.6.* is unaffected.
- Version 6.12.94, <= 6.12.* is unaffected.
- Version 6.18.36, <= 6.18.* is unaffected.
- Version 7.0.13, <= 7.0.* is unaffected.
- Version 7.1, <= * is unaffected.