CVE-2026-23146 - Vulnerability Details

- Bluetooth: hci_uart: fix null-ptr-deref in hci_uart_write_work

Description

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.

Published: 2026-02-14

Score: 5.5 Medium

EPSS: < 1% Very Low

KEV: No

Impact:

Action:

Analysis

Impact

The vulnerability is a race condition within the Bluetooth HCI over UART driver; a TTY write wakeup can schedule work before the UART instance is fully set up, causing a null pointer dereference in hci_uart_write_work. This triggers a kernel crash, leading to system unavailability and a forced reboot.

Affected Systems

Linux kernel builds containing the hci_uart driver are affected, including the release candidates of version 6.19 (rc1 through rc7) as listed in the CPE data. Administrators running these kernel releases should verify whether the patch has been applied.

Risk and Exploitability

With a CVSS score of 5.5 the flaw is of medium severity, and the EPSS score below 1% indicates a very low likelihood of exploitation. The vulnerability is not listed in the CISA KEV catalog. Exploitation would require a race between a TTY wakeup and driver initialization, and has no publicly documented attacker prerequisites. The likely attack vector is local, inferred from the need for a UART write wakeup during driver setup. Workarounds are limited, making the safest approach to update to a patched kernel version.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Linux

unaffected

Version	Status	Constraints
`a40f94f7caa8d3421b64f63ac31bc0f24c890f39`	affected	< b0a900939e7e4866d9b90e9112514b72c451e873
`9e5a0f5777162e503400c70c6ed25fbbe2d38799`	affected	< ccc683f597ceb28deb966427ae948e5ac739a909
`80f14e9de6a43a0bd8194cad1003a3e6dcbc3984`	affected	< 937a573423ce5a96fdb1fd425dc6b8d8d4ab5779
`02e1bcdfdf769974e7e9fa285e295cd9852e2a38`	affected	< 186d147cf7689ba1f9b3ddb753ab634a84940cc9
`281782d2c6730241e300d630bb9f200d831ede71`	affected	< 53e54cb31e667fca05b1808b990eac0807d1dab0
`5df5dafc171b90d0b8d51547a82657cd5a1986c7`	affected	< 03e8c90c62233382042b7bd0fa8b8900552fdb62
`5df5dafc171b90d0b8d51547a82657cd5a1986c7`	affected	< 0c3cd7a0b862c37acbee6d9502107146cc944398
`1dcf08fcff5ca529de6dc0395091f28854f4e54a`	affected	—
`8e5aff600539e5faea294d9612cca50220e602b8`	affected	—
`db7509fa110dd9b11134b75894677f30353b2c51`	affected	—
`5.10.237`	affected	< 5.10.249
`5.15.181`	affected	< 5.15.199
`6.1.135`	affected	< 6.1.162
`6.6.88`	affected	< 6.6.123
`6.12.24`	affected	< 6.12.69
`5.4.293`	affected	< 5.5
`6.13.12`	affected	< 6.14
`6.14.3`	affected	< 6.15

Linux

affected

Version	Status	Constraints
`6.15`	affected	—
`0`	unaffected	< 6.15
`5.10.249`	unaffected	≤ 5.10.*
`5.15.199`	unaffected	≤ 5.15.*
`6.1.162`	unaffected	≤ 6.1.*
`6.6.123`	unaffected	≤ 6.6.*
`6.12.69`	unaffected	≤ 6.12.*
`6.18.9`	unaffected	≤ 6.18.*
`6.19`	unaffected	≤ *

Configuration 1 [-]

OR	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel:6.19:rc1::::::
	cpe:2.3:o:linux:linux_kernel:6.19:rc2::::::
	cpe:2.3:o:linux:linux_kernel:6.19:rc3::::::
	cpe:2.3:o:linux:linux_kernel:6.19:rc4::::::
	cpe:2.3:o:linux:linux_kernel:6.19:rc5::::::
	cpe:2.3:o:linux:linux_kernel:6.19:rc6::::::
	cpe:2.3:o:linux:linux_kernel:6.19:rc7::::::

No data.

Vendor Product Confidence Versions

Linux

Linux Kernel

—

Version	Status	Scheme	Platform
`[a40f94f7caa8d3421b64f63ac31bc0f24c890f39,b0a900939e7e4866d9b90e9112514b72c451e873)`	affected	code_commit	—
`[9e5a0f5777162e503400c70c6ed25fbbe2d38799,ccc683f597ceb28deb966427ae948e5ac739a909)`	affected	code_commit	—
`[80f14e9de6a43a0bd8194cad1003a3e6dcbc3984,937a573423ce5a96fdb1fd425dc6b8d8d4ab5779)`	affected	code_commit	—
`[02e1bcdfdf769974e7e9fa285e295cd9852e2a38,186d147cf7689ba1f9b3ddb753ab634a84940cc9)`	affected	code_commit	—
`[281782d2c6730241e300d630bb9f200d831ede71,53e54cb31e667fca05b1808b990eac0807d1dab0)`	affected	code_commit	—
`[5df5dafc171b90d0b8d51547a82657cd5a1986c7,03e8c90c62233382042b7bd0fa8b8900552fdb62)`	affected	code_commit	—
`[5df5dafc171b90d0b8d51547a82657cd5a1986c7,0c3cd7a0b862c37acbee6d9502107146cc944398)`	affected	code_commit	—
`1dcf08fcff5ca529de6dc0395091f28854f4e54a`	affected	code_commit	—
`8e5aff600539e5faea294d9612cca50220e602b8`	affected	code_commit	—
`db7509fa110dd9b11134b75894677f30353b2c51`	affected	code_commit	—

Linux

Linux Kernel

—

Version	Status	Scheme	Platform
`6.15`	affected	generic	—
`[0,6.15)`	unaffected	generic	—
`[5.10.249,5.11.0)`	unaffected	semver	—
`[5.15.199,5.16.0)`	unaffected	semver	—
`[6.1.162,6.2.0)`	unaffected	semver	—
`[6.6.123,6.7.0)`	unaffected	semver	—
`[6.12.69,6.13.0)`	unaffected	semver	—
`[6.18.9,6.19.0)`	unaffected	semver	—
`[6.19,*]`	unaffected	generic	—

Found an issue or want to improve our Enrichment? You can suggest it directly by opening an issue on our dedicated GitHub repository .

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Apply the kernel update that includes the hci_uart fix (such as the latest patched kernel release).
If an immediate update is not possible, apply the upstream patch that moves set_bit(HCI_UART_PROTO_INIT) after proto->open() and recompile the kernel.
As a temporary containment measure, disable the Bluetooth HCI UART driver by unloading the module or removing it from the kernel configuration to prevent the race condition from occurring.

Generated by OpenCVE AI on October 23, 2026 at 08:45 UTC.

Tracking

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Advisories

Source	ID	Title
Ubuntu USN	USN-8162-1	Linux kernel (NVIDIA Tegra) vulnerabilities
Ubuntu USN	USN-8180-1	Linux kernel vulnerabilities
Ubuntu USN	USN-8180-2	Linux kernel (FIPS) vulnerabilities
Ubuntu USN	USN-8186-1	Linux kernel (Real-time) vulnerabilities
Ubuntu USN	USN-8187-1	Linux kernel (NVIDIA) vulnerabilities
Ubuntu USN	USN-8188-1	Linux kernel (HWE) vulnerabilities
Ubuntu USN	USN-8180-3	Linux kernel vulnerabilities
Ubuntu USN	USN-8180-4	Linux kernel (Azure FIPS) vulnerabilities
Ubuntu USN	USN-8180-5	Linux kernel (IBM) vulnerabilities
Ubuntu USN	USN-8243-1	Linux kernel (Azure) vulnerabilities
Ubuntu USN	USN-8180-6	Linux kernel (Raspberry Pi) vulnerabilities
Ubuntu USN	USN-8275-1	Linux kernel (Xilinx ZynqMP) vulnerabilities
Ubuntu USN	USN-8278-1	Linux kernel vulnerabilities
Ubuntu USN	USN-8289-1	Linux kernel (NVIDIA) vulnerabilities
Ubuntu USN	USN-8296-1	Linux kernel (FIPS) vulnerabilities
Ubuntu USN	USN-8297-1	Linux kernel (GCP) vulnerabilities
Ubuntu USN	USN-8296-2	Linux kernel (NVIDIA Tegra) vulnerabilities
Ubuntu USN	USN-8278-2	Linux kernel (Azure) vulnerabilities
Ubuntu USN	USN-8440-1	Linux kernel (Azure) vulnerabilities
Ubuntu USN	USN-8499-1	Linux kernel (Xilinx) vulnerabilities
Ubuntu USN	USN-8570-1	Linux kernel vulnerabilities
Ubuntu USN	USN-8594-1	Linux kernel (OEM) vulnerabilities
Ubuntu USN	USN-8604-1	Linux kernel (Azure) vulnerabilities
Ubuntu USN	USN-8605-1	Linux kernel (Azure CVM) vulnerabilities
Ubuntu USN	USN-8570-2	Linux kernel (Oracle) vulnerabilities
Ubuntu USN	USN-8289-2	Linux kernel (NVIDIA) vulnerabilities
Ubuntu USN	USN-8393-1	Linux kernel (Azure FIPS) vulnerabilities
Ubuntu USN	USN-8669-1	Linux kernel (NVIDIA) vulnerabilities

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00134.

Exploitation none

Automatable no

Technical Impact partial

References

Link	Providers
https://git.kernel.org/stable/c/03e8c90c62233382042b7bd0fa8b8900552fdb62
https://git.kernel.org/stable/c/0c3cd7a0b862c37acbee6d9502107146cc944398
https://git.kernel.org/stable/c/186d147cf7689ba1f9b3ddb753ab634a84940cc9
https://git.kernel.org/stable/c/53e54cb31e667fca05b1808b990eac0807d1dab0
https://git.kernel.org/stable/c/937a573423ce5a96fdb1fd425dc6b8d8d4ab5779
https://git.kernel.org/stable/c/b0a900939e7e4866d9b90e9112514b72c451e873
https://git.kernel.org/stable/c/ccc683f597ceb28deb966427ae948e5ac739a909
https://lore.kernel.org/linux-cve-announce/2026021411-CVE-2026-23146-3658@gregkh/T
https://nvd.nist.gov/vuln/detail/CVE-2026-23146
https://www.cve.org/CVERecord?id=CVE-2026-23146

History

Mon, 19 Oct 2026 19:30:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-362

Thu, 11 Jun 2026 19:30:00 +0000

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Tue, 17 Mar 2026 21:15:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-476
CPEs		cpe:2.3:o:linux:linux_kernel:6.19:rc1:::::: cpe:2.3:o:linux:linux_kernel:6.19:rc2:::::: cpe:2.3:o:linux:linux_kernel:6.19:rc3:::::: cpe:2.3:o:linux:linux_kernel:6.19:rc4:::::: cpe:2.3:o:linux:linux_kernel:6.19:rc5:::::: cpe:2.3:o:linux:linux_kernel:6.19:rc6:::::: cpe:2.3:o:linux:linux_kernel:6.19:rc7::::::
Metrics	cvssV3_1 `{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}`	cvssV3_1 `{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}`

Tue, 17 Feb 2026 00:15:00 +0000

Type	Values Removed	Values Added
References		https://lore.kernel.org/linux-cve-announce/2026021411-CVE-2026-23146-3658@gregkh/T https://nvd.nist.gov/vuln/detail/CVE-2026-23146 https://www.cve.org/CVERecord?id=CVE-2026-23146
Metrics	threat_severity `None`	cvssV3_1 `{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}` threat_severity `Important`

Sat, 14 Feb 2026 16:15:00 +0000

Type	Values Removed	Values Added
Description		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.
Title		Bluetooth: hci_uart: fix null-ptr-deref in hci_uart_write_work
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/03e8c90c62233382042b7bd0fa8b8900552fdb62 https://git.kernel.org/stable/c/0c3cd7a0b862c37acbee6d9502107146cc944398 https://git.kernel.org/stable/c/186d147cf7689ba1f9b3ddb753ab634a84940cc9 https://git.kernel.org/stable/c/53e54cb31e667fca05b1808b990eac0807d1dab0 https://git.kernel.org/stable/c/937a573423ce5a96fdb1fd425dc6b8d8d4ab5779 https://git.kernel.org/stable/c/b0a900939e7e4866d9b90e9112514b72c451e873 https://git.kernel.org/stable/c/ccc683f597ceb28deb966427ae948e5ac739a909

Subscriptions

Linux Linux Kernel

MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2026-02-14T16:01:16.169Z

Updated: 2026-10-19T18:25:33.428Z

Reserved: 2026-01-13T15:37:45.974Z

Link: CVE-2026-23146

Vulnrichment

Updated: 2026-06-11T17:38:49.920Z

NVD

Status : Modified

Published: 2026-02-14T16:15:54.703

Modified: 2026-10-19T19:17:39.357

Link: CVE-2026-23146

Redhat

Severity : Important

Publid Date: 2026-02-14T00:00:00Z

Links: CVE-2026-23146 - Bugzilla

OpenCVE Enrichment

Updated: 2026-10-23T09:00:15Z

Weaknesses

CWE-362
Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
CWE-476
NULL Pointer Dereference

Impact

Affected Systems

Risk and Exploitability

Tracking

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

Exploitation none

Automatable no

Technical Impact partial

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