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NVD / CVE Program· CNA Linux

CVE-2026-93209: Bluetooth: hci_core: use skb_get() instead of skb_clone() for req_skb

Noroxi assessment

Priority: Monitor (action score 0/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.17% (FIRST EPSS).
  • Fixed version: Linux Linux 0337fb092873a4146aa854acb554675b49c8f6b5, 26f66d5b8a5663af498f7ccc94fc79fb47a2191f, 6.1.118; azl3 kernel 6.6.150.1-1 on Azure Linux 3.0 6.6.157.1-1.

Low priority for now. Upgrade to Linux Linux 0337fb092873a4146aa854acb554675b49c8f6b5, 26f66d5b8a5663af498f7ccc94fc79fb47a2191f, 6.1.118; azl3 kernel 6.6.150.1-1 on Azure Linux 3.0 6.6.157.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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/

—No exploit Fix available
Published
Sep 24, 2026
Updated
Oct 19, 2026
EPSS
0.1% · 6th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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Noroxi analysis

What does it mean in your environment?

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 4ff121be63b761950610f422437aaaef8e075c40, 18a4c59af609994552c8b39c5438304e070e55c7, 6.9affected
    • da77c1d39bc527b31890bfa0405763c82828defb and later · before 0337fb092873a4146aa854acb554675b49c8f6b5affected · git
    • 2af7aa6685e22d0dc546b0d27e5f16d3afe211fa and later · before d5eef0747071934a1c080ee617fa4fd3566394c5affected · git
    • 2615fd9a7c2507eb3be3fbe49dcec88a2f56454a and later · before d7723320db4c9cb9ec2b9a36140e6c641dd77814affected · git
    • 2615fd9a7c2507eb3be3fbe49dcec88a2f56454a and later · before d0b28e9655f4b3195210627577f81883dc1d0162affected · git
    • 2615fd9a7c2507eb3be3fbe49dcec88a2f56454a and later · before 26f66d5b8a5663af498f7ccc94fc79fb47a2191faffected · git
    • 2615fd9a7c2507eb3be3fbe49dcec88a2f56454a and later · before f5afdff569a09d1cb8cf19826199d024725576cbaffected · git
    • 6.1.83 and later · before 6.1.118affected · semver
    • 6.6.23 and later · before 6.6.157affected · semver
    • 6.7.11 and later · before 6.8affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.119-16.1.119-1
Debian:12linux-6.12before 6.12.111-1~deb12u16.12.111-1~deb12u1
Debian:13linuxbefore 6.12.111-16.12.111-1
Debian:14linuxbefore 7.2.6-17.2.6-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-93207Sep 24, 2026 · SUNRPC: Zero rpc_gss_wire_cred at svcauth_gss_decode_credbody() entry
    39Monitor
  • ← EarlierCVE-2026-93208Sep 24, 2026 · kasan: fix cache shrink race with CPU hotplug
    0Monitor
  • Later →CVE-2026-93210Sep 24, 2026 · smb: client: harden DFS cache against invalid target hints
    0Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux0337fb092873a4146aa854acb554675b49c8f6b5Vendor (CNA)
Linux Linux26f66d5b8a5663af498f7ccc94fc79fb47a2191fVendor (CNA)
Linux Linux6.1.118Vendor (CNA)
Linux Linux6.6.157Vendor (CNA)
Linux Linux6.8Vendor (CNA)
Linux Linux6.9Vendor (CNA)
Linux Linuxd0b28e9655f4b3195210627577f81883dc1d0162Vendor (CNA)
Linux Linuxd5eef0747071934a1c080ee617fa4fd3566394c5Vendor (CNA)
Linux Linuxd7723320db4c9cb9ec2b9a36140e6c641dd77814Vendor (CNA)
Linux Linuxf5afdff569a09d1cb8cf19826199d024725576cbVendor (CNA)
azl3 kernel 6.6.150.1-1 on Azure Linux 3.06.6.157.1-1 · Release NotesMicrosoft (MSRC)
debian:linux6.1.119-1 · Debian:12Package registry (OSV)
debian:linux-6.126.12.111-1~deb12u1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

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References

Show all references (5 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records