CVE-2026-64405 — Bluetooth: hci_conn: Fix null ptr deref in hci_abort_conn()
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_conn: Fix null ptr deref in hci_abort_conn() hci_abort_conn() read hci_skb_event(hdev->sent_cmd) when a connection was pending, but hdev->sent_cmd can be NULL while req_status is still HCI_REQ_PEND, leading to a NULL pointer dereference and a general protection fault from the hci_rx_work() receive path. Instead of inspecting hdev->sent_cmd, track the in-flight create connection command with a new per-connection HCI_CONN_CREATE flag and route all cancellation through hci_cancel_connect_sync(), which dispatches to a dedicated per-type cancel function. The create command is in exactly one of two states: still queued, or in flight. The cancel function holds cmd_sync_work_lock across the whole decision: the worker takes this lock to dequeue every entry, so while it is held a queued command cannot start running and an in-flight command cannot complete and let the next command become pending. This keeps the flag test and hci_cmd_sync_cancel() atomic with respect to the worker, so a queued command is simply dequeued, and an in-flight command owned by this connection is cancelled without the risk of cancelling an unrelated command that became pending in the meantime. CIS uses the same flag mechanism via HCI_CONN_CREATE_CIS but cannot be dequeued per-connection. hci_acl_create_conn_sync() and hci_le_create_conn_sync() clear HCI_CONN_CREATE after the create command completes, but the command status handler can free conn via hci_conn_del() (for example when the controller rejects the connection) while the worker is still blocked on the connection complete event. Hold a reference on conn across the create command so the flag can be cleared without a use-after-free.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- Technical severity (medium)+3
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Linux Linux, Linux Linux Kernel).
- Apply the fixed version or the patch documented under Remediation.
- Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Linux | Linux |
≥ a13f316e90fdb1fb6df6582e845aa9b3270f3581 and < 70c397b62ee015e19b3924d9da741c8dda017819version 6.6≥ 6.5.3 and < 6.6≥ 6.4.16 and < 6.5≥ 6.1.83 and < 6.1.118version 4ab81f16c68a602b2b69e333ae08d8748a9398deversion e4511a67fcdba9729d1c7cfc6d2e645c765ce801≥ a13f316e90fdb1fb6df6582e845aa9b3270f3581 and < 12917f591cea1af36087dba5b9ec888652f0b42a and 4 more≥ a13f316e90fdb1fb6df6582e845aa9b3270f3581 and < b42cb640a0493d16b61ddd267420274be15efdc1≥ a13f316e90fdb1fb6df6582e845aa9b3270f3581 and < 61701912c58a05f6a043f097cc177a964abef348≥ a13f316e90fdb1fb6df6582e845aa9b3270f3581 and < 83b22d7f7c384564fa42c3cf19bec715c693d7a2≥ 6083089ab00631617f9eac678df3ab050a9d837a and < 903227b6168bb99fd57d4e3c9c1b5014986198e0 |
Vulnerable | CVE Program (cve.org) e CISA ADP |
| Linux | Linux Kernel | ≥ 6.1.83 and < 6.1.118version 7.2-rc2version 7.2-rc1≥ 6.19 and < 7.1.4≥ 6.13 and < 6.18.39≥ 6.7 and < 6.12.97≥ 6.5.3 and < 6.6.145≥ 6.4.16 and < 6.5 | Vulnerable | NIST National Vulnerability Database |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 5.5 | CVSS 3.1 | Medium | 1.8 | 3.6 | nvd@nist.gov via NIST National Vulnerability Database |
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H (score shown at the top: nvd@nist.gov) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
- Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · linux/linux
- Record published
- Fix documented
- CVSS changed · 5.5
- Source status changed · → Analyzed
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 15, 2026 – Oct 15, 2026
References
6 on the record
- git.kernel.org/stable/c/83b22d7f7c384564fa42c3cf19bec715c693d7a2
- git.kernel.org/stable/c/61701912c58a05f6a043f097cc177a964abef348
- git.kernel.org/stable/c/b42cb640a0493d16b61ddd267420274be15efdc1
- git.kernel.org/stable/c/70c397b62ee015e19b3924d9da741c8dda017819
- git.kernel.org/stable/c/12917f591cea1af36087dba5b9ec888652f0b42a
- git.kernel.org/stable/c/903227b6168bb99fd57d4e3c9c1b5014986198e0
Elsewhere on this site
Related CVEs (same products)
- Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 12h
- Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 12h
- Unknown CVE-2026-98431 RDMA/uverbs: Fix mmap_lock/disassociation_lock circular dependency 1d
- Unknown CVE-2026-98430 RDMA/efa: Keep admin queues alive while IRQ is registered 1d
- Unknown CVE-2026-98429 RDMA/efa: Keep EQ resources alive while IRQ is registered 1d
- Unknown CVE-2026-98428 ALSA: usb: 6fire: Avoid embedded URBs 1d
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No FIRST EPSS score.
- No CISA SSVC assessment.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-64405 is "Bluetooth: hci_conn: Fix null ptr deref in hci_abort_conn()", rated Medium. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.5 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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