CVE-2026-93209
- Source
- https://cve.org/CVERecord?id=CVE-2026-93209
- Import Source
- https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-93209.json
- JSON Data
- https://api.osv.dev/v1/vulns/CVE-2026-93209
- Downstream
- Related
- Published
- 2026-09-24T15:10:32Z
- Modified
- 2026-10-08T02:52:35Z
- Summary
- Bluetooth: hci_core: use skb_get() instead of skb_clone() for req_skb
- Details
-
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: hci_core: use skb_get() instead of skb_clone() for req_skb
BT enable fails intermittently with -ETIMEDOUT (-110). The kernel log shows the HCI Read Local Version command was sent and the firmware replied with status 0x00 (logged by hci_req_cmd_complete() BT_DBG), but the waiter in __hci_cmd_sync_sk() never woke up and timed out after 10 s:
bluetooth hci0: Opcode 0xfc00 // __hci_cmd_sync_sk bluetooth hci0: opcode 0xfc00 plen 1 // hci_cmd_sync_add bluetooth hci0: skb len 4 // hci_cmd_sync_alloc bluetooth hci0: length 1 // hci_req_sync_run Bluetooth: hci0 cmd_cnt 1 cmd queued 1 // hci_cmd_work Bluetooth: hci0 type 1 len 4 // hci_send_frame Bluetooth: opcode 0xfc00 status 0x00 // hci_req_cmd_complete <-- req_skb NULL: req_complete_skb not set, hci_cmd_sync_complete() never called, req_status stays HCI_REQ_PEND --> <-- 10 s later: wait_event_interruptible_timeout expires --> bluetooth hci0: end: err -110 // __hci_cmd_sync_sk
The root cause is that hci_send_cmd_sync() clones the sent command into hdev->req_skb so that hci_req_cmd_complete() can locate the registered completion callback. Under memory pressure this skb_clone() fails, leaving hdev->req_skb NULL. The firmware reply is received and processed, but hci_req_cmd_complete() finds NULL req_skb, so hci_cmd_sync_complete() is never called, req_status stays HCI_REQ_PEND, and the waiter times out with -ETIMEDOUT.
req_skb is only used to read bt_cb(skb)->hci callbacks and opcode -- it is never modified. Replace skb_clone() with skb_get(), which simply increments the reference count of hdev->sent_cmd without allocating new memory and therefore cannot fail.
This issue was first observed as a use-after-free in ttyport_close() when ttyport_open() failed, which was investigated in an earlier patch series [1]. That investigation led to the discovery of the true root cause described above.
[1] https://lore.kernel.org/all/20250430111617.1151390-1-quic_cxin@quicinc.com/
- Database specific
{ "cna_assigner": "Linux", "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/93xxx/CVE-2026-93209.json" }- References
-
- https://git.kernel.org/stable/c/0337fb092873a4146aa854acb554675b49c8f6b5
- https://git.kernel.org/stable/c/26f66d5b8a5663af498f7ccc94fc79fb47a2191f
- https://git.kernel.org/stable/c/d0b28e9655f4b3195210627577f81883dc1d0162
- https://git.kernel.org/stable/c/d5eef0747071934a1c080ee617fa4fd3566394c5
- https://git.kernel.org/stable/c/d7723320db4c9cb9ec2b9a36140e6c641dd77814
- https://git.kernel.org/stable/c/f5afdff569a09d1cb8cf19826199d024725576cb
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/93xxx/CVE-2026-93209.json
- https://nvd.nist.gov/vuln/detail/CVE-2026-93209
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Affected packages
Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Affected ranges
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introducedda77c1d39bc527b31890bfa0405763c82828defbFixed0337fb092873a4146aa854acb554675b49c8f6b5
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced2af7aa6685e22d0dc546b0d27e5f16d3afe211faFixedd5eef0747071934a1c080ee617fa4fd3566394c5
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced2615fd9a7c2507eb3be3fbe49dcec88a2f56454aFixedd7723320db4c9cb9ec2b9a36140e6c641dd77814Fixedd0b28e9655f4b3195210627577f81883dc1d0162Fixed26f66d5b8a5663af498f7ccc94fc79fb47a2191fFixedf5afdff569a09d1cb8cf19826199d024725576cb
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced6.1.83Fixed6.1.118
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced6.6.23Fixed6.6.157
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced6.7.11Fixed6.8
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced6.8.2Fixed6.9
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced4ff121be63b761950610f422437aaaef8e075c40
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced18a4c59af609994552c8b39c5438304e070e55c7
Affected versions
v6.*
Linux / Kernel
Package
- Name
- Kernel
Affected ranges
- Type
- ECOSYSTEM
- Events
-
Introduced0 Unknown introduced version / All previous versions are affectedFixed6.1.118
- Type
- ECOSYSTEM
- Events
-
Introduced6.2.0Fixed6.6.157
- Type
- ECOSYSTEM
- Events
-
Introduced6.7.0Fixed6.12.109
- Type
- ECOSYSTEM
- Events
-
Introduced6.9.0Fixed6.18.50
- Type
- ECOSYSTEM
- Events
-
Introduced6.13.0Fixed7.2.4