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CVE Record

CVE-2026-23146: Bluetooth: hci_uart: fix null-ptr-deref in hci_uart_write_work

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_uart: fix null-ptr-deref in hci_uart_write_work hci_uart_set_proto() sets HCI_UART_PROTO_INIT before calling hci_uart_register_dev(), which calls proto->open() to initialize hu->priv. However, if a TTY write wakeup occurs during this window, hci_uart_tx_wakeup() may schedule write_work before hu->priv is initialized, leading to a NULL pointer dereference in hci_uart_write_work() when proto->dequeue() accesses hu->priv. The race condition is: CPU0 CPU1 ---- ---- hci_uart_set_proto() set_bit(HCI_UART_PROTO_INIT) hci_uart_register_dev() tty write wakeup hci_uart_tty_wakeup() hci_uart_tx_wakeup() schedule_work(&hu->write_work) proto->open(hu) // initializes hu->priv hci_uart_write_work() hci_uart_dequeue() proto->dequeue(hu) // accesses hu->priv (NULL!) Fix this by moving set_bit(HCI_UART_PROTO_INIT) after proto->open() succeeds, ensuring hu->priv is initialized before any work can be scheduled.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This is a Linux kernel Bluetooth flaw that can crash kernel code when a Bluetooth UART setup race occurs. The public source describes a NULL pointer dereference, not data theft or remote code execution. Business urgency depends on whether affected Linux kernels use Bluetooth HCI UART paths.

Executive priority

Treat as a targeted kernel stability risk. Prioritize patching Bluetooth-capable Linux fleets, embedded devices, and systems where local crashes affect availability. Escalate if a vendor rates your platform higher or reports exploitation.

Technical view

In hci_uart_set_proto(), HCI_UART_PROTO_INIT was set before proto->open() initialized hu->priv. A TTY write wakeup could schedule hci_uart_write_work() early, causing proto->dequeue() to dereference NULL hu->priv. The fix moves the init bit until after proto->open() succeeds.

Likely exposure

Likely exposure is Linux systems running affected kernel builds with Bluetooth HCI UART support or UART-attached Bluetooth controllers. The bundle provides Linux version entries and stable commit references, but no CPEs or distribution package mapping.

Exploitation context

The bundle does not cite active exploitation, and KEV is false. The described issue is a timing race around TTY write wakeup during Bluetooth UART protocol initialization, with expected impact most consistent with kernel crash or denial of service.

Researcher notes

The evidence is limited to the CVE description and kernel stable references. No CVSS, CWE, exploit status, or distribution-specific advisory is included. Avoid broad claims beyond Bluetooth HCI UART race-triggered NULL pointer dereference.

Mitigation direction

  • Apply vendor kernel updates containing the referenced stable fixes.
  • Prioritize systems using Bluetooth HCI UART or embedded Bluetooth controllers.
  • If Bluetooth UART is unnecessary, disable it according to vendor guidance.
  • Track distribution advisories for package-specific fixed kernel versions.
  • Do not assume upstream version numbers equal distribution patch status.

Validation and detection

  • Inventory Linux kernel versions and distribution kernel package revisions.
  • Check whether Bluetooth HCI UART support is enabled or loaded.
  • Compare installed kernels against vendor advisories and referenced stable commits.
  • Review crash logs for NULL pointer dereference near hci_uart_write_work.
  • Confirm patched builds include the initialization-order fix.
Prepared
Confidence
medium
Sources
9

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2026-23146 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
8Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxa40f94f7caa8d3421b64f63ac31bc0f24c890f39, 9e5a0f5777162e503400c70c6ed25fbbe2d38799, 80f14e9de6a43a0bd8194cad1003a3e6dcbc3984, 02e1bcdfdf769974e7e9fa285e295cd9852e2a38, 281782d2c6730241e300d630bb9f200d831ede71, 5df5dafc171b90d0b8d51547a82657cd5a1986c7, 5df5dafc171b90d0b8d51547a82657cd5a1986c7, 1dcf08fcff5ca529de6dc0395091f28854f4e54a, 8e5aff600539e5faea294d9612cca50220e602b8, db7509fa110dd9b11134b75894677f30353b2c51, 5.10.237, 5.15.181, 6.1.135, 6.6.88, 6.12.24, 5.4.293, 6.13.12, 6.14.3unaffected
LinuxLinux6.15, 0, 5.10.249, 5.15.199, 6.1.162, 6.6.123, 6.12.69, 6.18.9, 6.19affected
Weakness

CWE details

No CWE listed

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