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VulnerabilityPublished Updated

CVE-2026-64557: Linux kernel · Bluetooth: L2CAP: Fix use-after-free in l2cap_sock_new_connection_cb()

Affects Linux kernelSource CVE Database V5

0

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

CVSS 3.1 base score
8.8High
How severe the flaw is on the 0–10 CVSS scale.
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:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 29 Jul 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 8ffb929098a56939ac71509302eeab5b207bf262, < b39298044e5534612511a2ff5de03ba5f6e7a820
Fixed in
  • b39298044e5534612511a2ff5de03ba5f6e7a820
LinuxLinuxAffected
  • ≥ 8ffb929098a56939ac71509302eeab5b207bf262, < 733e76e74e406c1d1ddc7369420dd8a47f48bb8a
Fixed in
  • 733e76e74e406c1d1ddc7369420dd8a47f48bb8a
LinuxLinuxAffected
  • ≥ 8ffb929098a56939ac71509302eeab5b207bf262, < 84e718b6a814edc84159361f9f454a4e92ae91ae
Fixed in
  • 84e718b6a814edc84159361f9f454a4e92ae91ae
LinuxLinuxAffected
  • ≥ 8ffb929098a56939ac71509302eeab5b207bf262, < 36da806f7fbaee56ad9e81859deec203f9728700
Fixed in
  • 36da806f7fbaee56ad9e81859deec203f9728700
LinuxLinuxAffected
  • ≥ 8ffb929098a56939ac71509302eeab5b207bf262, < 8c37e4338c801ebb8cee52436c01c41e009f6e87
Fixed in
  • 8c37e4338c801ebb8cee52436c01c41e009f6e87
LinuxLinuxAffected
  • ≥ 8ffb929098a56939ac71509302eeab5b207bf262, < 6fef032af0092ed5ccb767239a9ac1bc38c08a40
Fixed in
  • 6fef032af0092ed5ccb767239a9ac1bc38c08a40

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

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