Bluetooth: SCO: fix race conditions in sco_sock_connect()

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Summary

CVECVE-2026-43023
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-05-01 15:16:46 UTC
Updated2026-05-01 15:24:14 UTC
DescriptionIn 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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 70a13b1e25fef37c87c8a1228ddb8900efbca7cf dabf22269242e2f2bf44c43fcdc2fa763df7f9cc git Not specified
CNA Linux Linux affected 9a8ec9e8ebb5a7c0cfbce2d6b4a6b67b2b78e8f3 adb90cd0f9f7a8d438fcb93354040fbafc5ae2a0 git Not specified
CNA Linux Linux affected 9a8ec9e8ebb5a7c0cfbce2d6b4a6b67b2b78e8f3 7e296ffdab5bdab718dff7c14288fdcb9154fa27 git Not specified
CNA Linux Linux affected 9a8ec9e8ebb5a7c0cfbce2d6b4a6b67b2b78e8f3 98c8d3bfdaa657d8f472dbbebd7ea8cd816d8a8d git Not specified
CNA Linux Linux affected 9a8ec9e8ebb5a7c0cfbce2d6b4a6b67b2b78e8f3 d002bd11024bd231bcb606877e33951ffb7bed14 git Not specified
CNA Linux Linux affected 9a8ec9e8ebb5a7c0cfbce2d6b4a6b67b2b78e8f3 8a5b0135d4a5d9683203a3d9a12a711ccec5936b git Not specified
CNA Linux Linux affected 6.3 Not specified
CNA Linux Linux unaffected 6.3 semver Not specified
CNA Linux Linux unaffected 6.1.168 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.134 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.81 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.22 6.18.* semver Not specified
CNA Linux Linux unaffected 6.19.12 6.19.* semver Not specified
CNA Linux Linux unaffected 7.0 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/dabf22269242e2f2bf44c43fcdc2fa763df7f9cc 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/7e296ffdab5bdab718dff7c14288fdcb9154fa27 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/8a5b0135d4a5d9683203a3d9a12a711ccec5936b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/98c8d3bfdaa657d8f472dbbebd7ea8cd816d8a8d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/adb90cd0f9f7a8d438fcb93354040fbafc5ae2a0 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/d002bd11024bd231bcb606877e33951ffb7bed14 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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