CVE-2026-23146: Linux kernel · Bluetooth: hci_uart: fix null-ptr-deref in hci_uart_write_work
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 5.15.0-1105.112~20.04.1 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.15.0-1105.112~20.04.1, 5.15.0-1110.119~20.04.1, 5.15.0-1106.115~20.04.1 +65
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 14 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Patches and advisories
- ubuntu.com/security/notices/USN-8162-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8180-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8180-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8186-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8187-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8188-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8180-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8180-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8180-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-8243-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8180-6 (opens in a new tab)
- ubuntu.com/security/notices/USN-8275-1 (opens in a new tab)
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 25.10linuxpkg:deb/ubuntu/linux?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-oraclepkg:deb/ubuntu/linux-oracle?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
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.
References
- ubuntu.com/security/CVE-2026-23146 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-23146 (opens in a new tab)
- git.kernel.org/linus/0c3cd7a0b862c37acbee6d9502107146cc944398 (opens in a new tab)
- git.kernel.org/stable/c/03e8c90c62233382042b7bd0fa8b8900552fdb62 (opens in a new tab)
- git.kernel.org/stable/c/0c3cd7a0b862c37acbee6d9502107146cc944398 (opens in a new tab)
- git.kernel.org/stable/c/186d147cf7689ba1f9b3ddb753ab634a84940cc9 (opens in a new tab)
- git.kernel.org/stable/c/53e54cb31e667fca05b1808b990eac0807d1dab0 (opens in a new tab)
- git.kernel.org/stable/c/937a573423ce5a96fdb1fd425dc6b8d8d4ab5779 (opens in a new tab)
- git.kernel.org/stable/c/b0a900939e7e4866d9b90e9112514b72c451e873 (opens in a new tab)
- git.kernel.org/stable/c/ccc683f597ceb28deb966427ae948e5ac739a909 (opens in a new tab)
- ubuntu.com/security/notices/USN-8162-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8180-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8180-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8186-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8187-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8188-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8180-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8180-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8180-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-8243-1 (opens in a new tab)