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Review reviewHigh

CVE-2026-23461

Linux Linux, linux kernel

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: Fix use-after-free in l2cap_unregister_user After commit ab4eedb790ca ("Bluetooth: L2CAP: Fix corrupted list in hci_chan_del"), l2cap_conn_del() uses conn->lock to protect access to conn->users. However, l2cap_register_user() and l2cap_unregister_user() don't use conn->lock, creating a race condition where these functions can access conn->users and conn->hchan concurrently with l2cap_conn_del(). This can lead to use-after-free and list corruption bugs, as reported by syzbot. Fix this by changing l2cap_regi...

CVSS
8.8
EPSS
0.25%
16.1% percentile
CISA KEV
Not listed
Published
2026.04.04
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.25%
Technical severityCVSS 8.8

Vulnerability overview

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: Fix use-after-free in l2cap_unregister_user After commit ab4eedb790ca ("Bluetooth: L2CAP: Fix corrupted list in hci_chan_del"), l2cap_conn_del() uses conn->lock to protect access to conn->users. However, l2cap_register_user() and l2cap_unregister_user() don't use conn->lock, creating a race condition where these functions can access conn->users and conn->hchan concurrently with l2cap_conn_del(). This can lead to use-after-free and list corruption bugs, as reported by syzbot. Fix this by changing l2cap_regi...

Affected product and versions

Product
Linux Linux, linux kernel
Affected versions
>= efc30877bd4bc85fefe98d80af60fafc86e5775e < 11a87dd5df428a4b79a84d2790cac7f3c73f1f0d, >= f87271d21dd4ee83857ca11b94e7b4952749bbae < c22a5e659959eb77c2fbb58a5adfaf3c3dab7abf, >= ab4eedb790cae44313759b50fe47da285e2519d5 < da3000cbe4851458a22be38bb18c0689c39fdd5f, >= ab4eedb790cae44313759b50fe47da285e2519d5 < 71030f3b3015a412133a805ff47970cdcf30c2b8, >= ab4eedb790cae44313759b50fe47da285e2519d5 < 752a6c9596dd25efd6978a73ff21f3b592668f4a, >= 18ab6b6078fa8191ca30a3065d57bf35d5635761, >= 6.6.84 < 6.6.130, >= 6.12.20 < 6.12.78, >= 6.13.8 < 6.14, >= 6.14, >= 6.14.1 < 6.18.20, >= 6.19 < 6.19.10, 6.14, 7.0
Fixed versions
6.6.130, 6.12.78, 6.14, 6.18.20, 6.19.10

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux Linux, linux kernel and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE
CWE-416
CVE-2026-23461 — Linux Linux, linux kernel | SECUFOCUS NOW