CVE-2026-53256: Linux kernel · Bluetooth: RFCOMM: hold listener socket in rfcomm_connect_ind()
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 8.0 High · fixed in f5ec76bdbeb80f75ad0be204371afffee0f8fac8 : patch Linux kernel soon.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 18% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-10-16.
- Patch
- Available – fixed in f5ec76bdbeb80f75ad0be204371afffee0f8fac8, de31973ef00e5aa55496f84cf6a44bb157a34e02, b0e33e409715c617e2a20f46f99aa5403a14dfda +5
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 25 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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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().
References
- git.kernel.org/stable/c/f5ec76bdbeb80f75ad0be204371afffee0f8fac8 (opens in a new tab)
- git.kernel.org/stable/c/a07d741c077d4e34b16458241a94d29039386553 (opens in a new tab)
- git.kernel.org/stable/c/1f73f92f66251065a5f39b09a47cf05ea14d3107 (opens in a new tab)
- git.kernel.org/stable/c/de31973ef00e5aa55496f84cf6a44bb157a34e02 (opens in a new tab)
- git.kernel.org/stable/c/b0e33e409715c617e2a20f46f99aa5403a14dfda (opens in a new tab)
- git.kernel.org/stable/c/8802413ce63175fb522a2bd609fb043a3550c720 (opens in a new tab)
- git.kernel.org/stable/c/6f4462d12133106460d7c046b95aad2491e3fddf (opens in a new tab)
- git.kernel.org/stable/c/43c441edacf953b39517a44f5e5e10a93618b226 (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-784472.html (opens in a new tab)