CVE-2026-64557: Linux kernel · Bluetooth: L2CAP: Fix use-after-free in l2cap_sock_new_connection_cb()
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 8.8 High · fixed in b39298044e5534612511a2ff5de03ba5f6e7a820 : patch Linux kernel soon.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 21% 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 b39298044e5534612511a2ff5de03ba5f6e7a820, 733e76e74e406c1d1ddc7369420dd8a47f48bb8a, 84e718b6a814edc84159361f9f454a4e92ae91ae +3
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 29 Jul 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: L2CAP: Fix use-after-free in l2cap_sock_new_connection_cb() l2cap_sock_new_connection_cb() returned l2cap_pi(sk)->chan after release_sock(parent). Once the parent lock is dropped the newly enqueued child socket sk is reachable via the accept queue, so another task can accept and free it before the callback dereferences sk, resulting in a use-after-free. Rework the ->new_connection() op so the core, rather than the callback, owns the child channel's lifetime. The op now receives a pre-allocated new_chan and returns an errno instead of allocating and returning a channel. l2cap_new_connection() allocates the child channel and links it into the conn list via __l2cap_chan_add() before invoking the callback, so the conn-list reference keeps the channel alive once release_sock(parent) exposes the socket to other tasks. Channel configuration that was duplicated in l2cap_sock_init() and the various new_connection callbacks is consolidated into l2cap_chan_set_defaults(), which now inherits from the parent channel when one is supplied.
References
- git.kernel.org/stable/c/b39298044e5534612511a2ff5de03ba5f6e7a820 (opens in a new tab)
- git.kernel.org/stable/c/8c37e4338c801ebb8cee52436c01c41e009f6e87 (opens in a new tab)
- git.kernel.org/stable/c/84e718b6a814edc84159361f9f454a4e92ae91ae (opens in a new tab)
- git.kernel.org/stable/c/36da806f7fbaee56ad9e81859deec203f9728700 (opens in a new tab)
- git.kernel.org/stable/c/733e76e74e406c1d1ddc7369420dd8a47f48bb8a (opens in a new tab)
- git.kernel.org/stable/c/6fef032af0092ed5ccb767239a9ac1bc38c08a40 (opens in a new tab)