CVE-2026-43023
Description
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: SCO: fix race conditions in sco_sock_connect() sco_sock_connect() checks sk_state and sk_type without holding the socket lock. Two concurrent connect() syscalls on the same socket can both pass the check and enter sco_connect(), leading to use-after-free. The buggy scenario involves three participants and was confirmed with additional logging instrumentation: Thread A (connect): HCI disconnect: Thread B (connect): sco_sock_connect(sk) sco_sock_connect(sk) sk_state==BT_OPEN sk_state==BT_OPEN (pass, no lock) (pass, no lock) sco_connect(sk): sco_connect(sk): hci_dev_lock hci_dev_lock hci_connect_sco <- blocked -> hcon1 sco_conn_add->conn1 lock_sock(sk) sco_chan_add: conn1->sk = sk sk->conn = conn1 sk_state=BT_CONNECT release_sock hci_dev_unlock hci_dev_lock sco_conn_del: lock_sock(sk) sco_chan_del: sk->conn=NULL conn1->sk=NULL sk_state= BT_CLOSED SOCK_ZAPPED release_sock hci_dev_unlock (unblocked) hci_connect_sco -> hcon2 sco_conn_add -> conn2 lock_sock(sk) sco_chan_add: sk->conn=conn2 sk_state= BT_CONNECT // zombie sk! release_sock hci_dev_unlock Thread B revives a BT_CLOSED + SOCK_ZAPPED socket back to BT_CONNECT. Subsequent cleanup triggers double sock_put() and use-after-free. Meanwhile conn1 is leaked as it was orphaned when sco_conn_del() cleared the association. Fix this by: - Moving lock_sock() before the sk_state/sk_type checks in sco_sock_connect() to serialize concurrent connect attempts - Fixing the sk_type != SOCK_SEQPACKET check to actually return the error instead of just assigning it - Adding a state re-check in sco_connect() after lock_sock() to catch state changes during the window between the locks - Adding sco_pi(sk)->conn check in sco_chan_add() to prevent double-attach of a socket to multiple connections - Adding hci_conn_drop() on sco_chan_add failure to prevent HCI connection leaks
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
Linux kernel Affected 3 releases
| Version | Status | Fixed in |
|---|---|---|
| 7.0 | Affected | — |
| 6.3 | Affected | — |
| — | Affected | 6.1.168 |
SUSE Affected 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Affected | — |
Debian Fixed 5 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Fixed | 6.12.85-1 |
| sid | Fixed | 6.19.12-1 |
| forky | Fixed | 6.19.12-1 |
| bullseye | Fixed | 0 |
| bookworm | Fixed | 6.1.170-1 |
Red Hat Fixed 1 release
| Version | Status | Fixed in |
|---|---|---|
| 9 | Fixed | — |
References
- https://git.kernel.org/stable/c/7e296ffdab5bdab718dff7c14288fdcb9154fa27
- https://git.kernel.org/stable/c/8a5b0135d4a5d9683203a3d9a12a711ccec5936b
- https://git.kernel.org/stable/c/98c8d3bfdaa657d8f472dbbebd7ea8cd816d8a8d
- https://git.kernel.org/stable/c/adb90cd0f9f7a8d438fcb93354040fbafc5ae2a0
- https://git.kernel.org/stable/c/d002bd11024bd231bcb606877e33951ffb7bed14
- https://git.kernel.org/stable/c/dabf22269242e2f2bf44c43fcdc2fa763df7f9cc
- https://www.suse.com/security/cve/CVE-2026-43023.html
- https://security-tracker.debian.org/tracker/CVE-2026-43023
- https://access.redhat.com/errata/RHSA-2026:21556
CWEs
CWE-362
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.