CVE-2026-90091

High

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: fix race l2cap_sock_cleanup_listen() vs. put_chan For L2CAP sockets without owning sk->sk_socket, reading l2cap_pi(sk)->chan may race against concurrent l2cap_sock_kill() -> l2cap_sock_put_chan(). This excludes simultaneous proto_ops callbacks, but access in l2cap_sock_cleanup_listen() has unsafe lockless read. [Task 1] [Task 2 (hdev->workqueue)] l2cap_sock_release(parent) l2cap_disconn_cfm l2cap_sock_cleanup_listen l2cap_conn_del bt_accept_dequeue l2cap_chan_del lock_sock(sk) l2cap_sock_teardown_cb bt_accept_unlink bt_sk(sk)->parent = NULL release_sock(sk) ----------------> lock_sock(sk) parent = /* NULL */ lock_sock(sk) <--------------------- release_sock(sk) sock_set_flag(sk, SOCK_ZAPPED) l2cap_sock_close_cb l2cap_sock_kill(sk) l2cap_sock_put_chan chan = READ l2cap_pi(sk)->chan l2cap_pi(sk)->chan = NULL l2cap_chan_hold_unless_zero l2cap_put_chan(chan) kref_get_unless_zero(&chan->ref) Task 1 may observe NULL which causes null-ptr-deref. Fix the race by taking lock_sock() in l2cap_sock_kill() to synchronize with l2cap_sock_cleanup_listen(). hold_unless_zero() is not needed here, l2cap_pi(sk)->chan owns reference if it is non-NULL. Clarify code comments vs. locking.

Package Linux Kernel
Published 2026-09-17
Last modified 2026-09-18
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

8.0

out of 10
High
Attack Vector
Adjacent
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Vector string
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected versions

Linux kernel versions 6.1.178, 6.6.145, 6.12.97, 6.18.40, 7.1.5, 7.2 and later are affected. Fixed in 6.1.188, 6.6.157, 6.12.110, 6.18.52, 7.2.6, 7.3-rc1 and their respective stable series.

Affected from
≥ 6.1.178 ≥ 6.6.145 ≥ 6.12.97 ≥ 6.18.40 ≥ 7.1.5 ≥ 7.2
Fixed in
✓ 6.1.188 6.1.x ✓ 6.6.157 6.6.x ✓ 6.12.110 6.12.x ✓ 6.18.52 6.18.x ✓ 7.2.6 7.2.x ✓ 7.3-rc1

References

6 total
Showing 5 of 6 references View all on NVD

Frequently asked questions

  • What is CVE-2026-90091?

    CVE-2026-90091 is a High severity Linux kernel vulnerability with a CVSS score of 8.0 out of 10 . It affects Linux kernel versions from 6.1.178 onward and has been patched in 6.1.188, 6.6.157, 6.12.110 and others. CVE-2026-90091 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2026-90091?

    CVE-2026-90091 has a CVSS score of 8.0 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H .

  • Is there a patch available for CVE-2026-90091?

    Yes. CVE-2026-90091 has been patched. Fixed versions include 6.1.188, 6.6.157, 6.12.110 and others. If you are running Linux kernel 6.1.178 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2026-90091 actively exploited?

    No. CVE-2026-90091 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

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