CVE-2026-99008 - Vulnerability Details

- Bluetooth: RFCOMM: Fix NULL tty_dev dereference in rfcomm_dev_shutdown

Description

In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: RFCOMM: Fix NULL tty_dev dereference in rfcomm_dev_shutdown

syzbot hit a NULL pointer dereference in rfcomm_dev_shutdown() when an
RFCOMM tty is closed.

rfcomm_dev_add() puts the new device on rfcomm_dev_list first and only
then registers the tty device and saves it in dev->tty_dev. If that
registration fails, dev->tty_dev is never set at all. The device can be
looked up in the meantime, so an open() of /dev/rfcommN gets through
rfcomm_tty_install() and attaches to it. When that tty is closed again,
rfcomm_dev_shutdown() uses dev->tty_dev without checking it:

Oops: general protection fault, probably for non-canonical address
KASAN: null-ptr-deref in range [0x0000000000000040-0x0000000000000047]
RIP: 0010:rfcomm_dev_shutdown+0x48/0xb0 net/bluetooth/rfcomm/tty.c:131
Call Trace:
tty_port_shutdown+0x1bf/0x220 drivers/tty/tty_port.c:372
tty_port_close+0x4e/0x150 drivers/tty/tty_port.c:705
tty_release+0x359/0x1670 drivers/tty/tty_io.c:1718
__fput+0x418/0xa50 fs/file_table.c:512

rfcomm_dev_destruct() already copes with a NULL dev->tty_dev. Add the
same check to rfcomm_dev_shutdown(), so the tty device is only moved
when it was actually registered.

Published: 2026-10-23

Score: 4.1 Medium

EPSS: < 1% Very Low

KEV: No

Impact:

Action:

Analysis

Impact

A NULL pointer dereference occurs in the Linux kernel’s RFCOMM device shutdown routine. When an RFCOMM tty device is closed, the function rfcomm_dev_shutdown() accesses dev->tty_dev without confirming it is set, leading to a kernel panic and a system reboot. The flaw is triggered specifically during the shutdown of an RFCOMM tty, which can be invoked by a user or an attacker controlling a Bluetooth connection.

Affected Systems

The vulnerability affects all Linux kernel installations that have not yet applied the specified patch, regardless of distribution. The issue resides in the core Bluetooth RFCOMM implementation, so any platform running a Linux kernel version before the fix is potentially impacted.

Risk and Exploitability

The CVSS score of 4.1 indicates moderate severity, and the EPSS score of less than 1% suggests a low likelihood of exploitation. Based on the description, it is inferred that an attacker could trigger the crash by opening and closing an RFCOMM tty over a Bluetooth interface. The flaw is not listed in the CISA KEV catalog, and no public exploits are known, but a kernel panic leads to a Denial of Service outcome that requires a reboot to recover.

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
`cad348a17e170451ea8688b532a6ca3e98c63b60`	affected	< b2b915042be073637d9f93dc51ef15fc0685ae8a
`cad348a17e170451ea8688b532a6ca3e98c63b60`	affected	< a43452d8c1015ac2f0e43ff946be5425427b02cc
`cad348a17e170451ea8688b532a6ca3e98c63b60`	affected	< 3f6394f6c6d1b6817065d3b402f55d437063a704
`cad348a17e170451ea8688b532a6ca3e98c63b60`	affected	< d5c372ad03330f02962d4860df4d355ab25487df
`cad348a17e170451ea8688b532a6ca3e98c63b60`	affected	< 3fd5164bdb04635caa7942ddb554b0ec699a9433
`cad348a17e170451ea8688b532a6ca3e98c63b60`	affected	< a661f401f83b8462f2d424e0a1a72b7681e92ea2
`cad348a17e170451ea8688b532a6ca3e98c63b60`	affected	< d0aef0b0374678153244f162df507106d728af39
`cad348a17e170451ea8688b532a6ca3e98c63b60`	affected	< 08e90633377f1b2567ab5ad6810b74c552246a07

Linux

affected

Version	Status	Constraints
`3.12`	affected	—
`0`	unaffected	< 3.12
`5.10.273`	unaffected	≤ 5.10.*
`5.15.224`	unaffected	≤ 5.15.*
`6.1.191`	unaffected	≤ 6.1.*
`6.6.160`	unaffected	≤ 6.6.*
`6.12.113`	unaffected	≤ 6.12.*
`6.18.57`	unaffected	≤ 6.18.*
`7.2.11`	unaffected	≤ 7.2.*
`7.3`	unaffected	≤ *

No data.

Vendor Product Confidence Versions

Linux

100%

Version	Status	Scheme	Platform
`[cad348a17e170451ea8688b532a6ca3e98c63b60,d5c372ad03330f02962d4860df4d355ab25487df)`	affected	code_commit	—
`[cad348a17e170451ea8688b532a6ca3e98c63b60,3fd5164bdb04635caa7942ddb554b0ec699a9433)`	affected	code_commit	—
`[cad348a17e170451ea8688b532a6ca3e98c63b60,a661f401f83b8462f2d424e0a1a72b7681e92ea2)`	affected	code_commit	—
`[cad348a17e170451ea8688b532a6ca3e98c63b60,d0aef0b0374678153244f162df507106d728af39)`	affected	code_commit	—
`[cad348a17e170451ea8688b532a6ca3e98c63b60,08e90633377f1b2567ab5ad6810b74c552246a07)`	affected	code_commit	—

Linux

100%

Version	Status	Scheme	Platform
`3.12`	affected	generic	—
`[0,3.12)`	unaffected	generic	—
`[6.6.160,6.7.0)`	unaffected	generic	—
`[6.12.113,6.13.0)`	unaffected	generic	—
`[6.18.57,6.19.0)`	unaffected	generic	—
`[7.2.11,7.3.0)`	unaffected	generic	—
`[7.3,*]`	unaffected	generic	—

Linux

Linux Kernel

100%

Version	Status	Scheme	Platform
`[cad348a17e170451ea8688b532a6ca3e98c63b60,d5c372ad03330f02962d4860df4d355ab25487df)`	affected	code_commit	—
`[cad348a17e170451ea8688b532a6ca3e98c63b60,3fd5164bdb04635caa7942ddb554b0ec699a9433)`	affected	code_commit	—
`[cad348a17e170451ea8688b532a6ca3e98c63b60,a661f401f83b8462f2d424e0a1a72b7681e92ea2)`	affected	code_commit	—
`[cad348a17e170451ea8688b532a6ca3e98c63b60,d0aef0b0374678153244f162df507106d728af39)`	affected	code_commit	—
`[cad348a17e170451ea8688b532a6ca3e98c63b60,08e90633377f1b2567ab5ad6810b74c552246a07)`	affected	code_commit	—

Linux

Linux Kernel

100%

Version	Status	Scheme	Platform
`3.12`	affected	generic	—
`[0,3.12)`	unaffected	generic	—
`[6.6.160,6.7.0)`	unaffected	generic	—
`[6.12.113,6.13.0)`	unaffected	generic	—
`[6.18.57,6.19.0)`	unaffected	generic	—
`[7.2.11,7.3.0)`	unaffected	generic	—
`[7.3,*]`	unaffected	generic	—

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Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Apply a kernel update that includes the RFCOMM NULL pointer dereference fix
If updating is not immediately possible, disable the rfcomm driver or Bluetooth services until the patch is applied
Ensure that any active RFCOMM connections are closed after applying the update to prevent accidental re‑triggering of the crash

Generated by OpenCVE AI on October 29, 2026 at 19:12 UTC.

Tracking

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Advisories

Source	ID	Title
Ubuntu USN	USN-9018-1	Linux kernel vulnerabilities
Ubuntu USN	USN-9018-2	Linux kernel (HWE) vulnerabilities
Ubuntu USN	USN-9019-1	Linux kernel (Azure) vulnerabilities
Ubuntu USN	USN-9020-1	Linux kernel vulnerabilities
Ubuntu USN	USN-9022-1	Linux kernel vulnerabilities
Ubuntu USN	USN-9023-1	Linux kernel vulnerabilities
Ubuntu USN	USN-9024-1	Linux kernel vulnerabilities
Ubuntu USN	USN-9025-1	Linux kernel vulnerabilities
Ubuntu USN	USN-9026-1	Linux kernel (Azure) vulnerabilities
Ubuntu USN	USN-9039-1	Linux kernel (Azure CVM) vulnerabilities
Ubuntu USN	USN-9040-1	Linux kernel (Low Latency NVIDIA) vulnerabilities
Ubuntu USN	USN-9066-1	Linux kernel (HWE) vulnerabilities

No CVSS v4.0

Attack Vector Local

Attack Complexity High

Privileges Required High

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 0.00177.

Key SSVC decision points have not yet been added.

References

Link	Providers
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-99008.mbox
https://git.kernel.org/stable/c/08e90633377f1b2567ab5ad6810b74c552246a07
https://git.kernel.org/stable/c/3f6394f6c6d1b6817065d3b402f55d437063a704
https://git.kernel.org/stable/c/3fd5164bdb04635caa7942ddb554b0ec699a9433
https://git.kernel.org/stable/c/a43452d8c1015ac2f0e43ff946be5425427b02cc
https://git.kernel.org/stable/c/a661f401f83b8462f2d424e0a1a72b7681e92ea2
https://git.kernel.org/stable/c/b2b915042be073637d9f93dc51ef15fc0685ae8a
https://git.kernel.org/stable/c/d0aef0b0374678153244f162df507106d728af39
https://git.kernel.org/stable/c/d5c372ad03330f02962d4860df4d355ab25487df
https://nvd.nist.gov/vuln/detail/CVE-2026-99008
https://www.cve.org/CVERecord?id=CVE-2026-99008

History

Fri, 30 Oct 2026 13:00:00 +0000

Type	Values Removed	Values Added
References		https://git.kernel.org/stable/c/3f6394f6c6d1b6817065d3b402f55d437063a704 https://git.kernel.org/stable/c/a43452d8c1015ac2f0e43ff946be5425427b02cc https://git.kernel.org/stable/c/b2b915042be073637d9f93dc51ef15fc0685ae8a

Thu, 29 Oct 2026 12:15:00 +0000

Type	Values Removed	Values Added
References		https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-99008.mbox https://nvd.nist.gov/vuln/detail/CVE-2026-99008 https://www.cve.org/CVERecord?id=CVE-2026-99008
Metrics	threat_severity `None`	cvssV3_1 `{'score': 4.1, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H'}` threat_severity `Moderate`

Fri, 23 Oct 2026 19:30:00 +0000

Type	Values Removed	Values Added
First Time appeared		Linux linux
Vendors & Products		Linux linux

Fri, 23 Oct 2026 15:45:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-476

Fri, 23 Oct 2026 12:45:00 +0000

Type	Values Removed	Values Added
Description		In the Linux kernel, the following vulnerability has been resolved: Bluetooth: RFCOMM: Fix NULL tty_dev dereference in rfcomm_dev_shutdown syzbot hit a NULL pointer dereference in rfcomm_dev_shutdown() when an RFCOMM tty is closed. rfcomm_dev_add() puts the new device on rfcomm_dev_list first and only then registers the tty device and saves it in dev->tty_dev. If that registration fails, dev->tty_dev is never set at all. The device can be looked up in the meantime, so an open() of /dev/rfcommN gets through rfcomm_tty_install() and attaches to it. When that tty is closed again, rfcomm_dev_shutdown() uses dev->tty_dev without checking it: Oops: general protection fault, probably for non-canonical address KASAN: null-ptr-deref in range [0x0000000000000040-0x0000000000000047] RIP: 0010:rfcomm_dev_shutdown+0x48/0xb0 net/bluetooth/rfcomm/tty.c:131 Call Trace: tty_port_shutdown+0x1bf/0x220 drivers/tty/tty_port.c:372 tty_port_close+0x4e/0x150 drivers/tty/tty_port.c:705 tty_release+0x359/0x1670 drivers/tty/tty_io.c:1718 __fput+0x418/0xa50 fs/file_table.c:512 rfcomm_dev_destruct() already copes with a NULL dev->tty_dev. Add the same check to rfcomm_dev_shutdown(), so the tty device is only moved when it was actually registered.
Title		Bluetooth: RFCOMM: Fix NULL tty_dev dereference in rfcomm_dev_shutdown
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/08e90633377f1b2567ab5ad6810b74c552246a07 https://git.kernel.org/stable/c/3fd5164bdb04635caa7942ddb554b0ec699a9433 https://git.kernel.org/stable/c/a661f401f83b8462f2d424e0a1a72b7681e92ea2 https://git.kernel.org/stable/c/d0aef0b0374678153244f162df507106d728af39 https://git.kernel.org/stable/c/d5c372ad03330f02962d4860df4d355ab25487df

Subscriptions

Linux Linux Linux Kernel

MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2026-10-23T12:20:33.355Z

Updated: 2026-10-30T12:40:53.373Z

Reserved: 2026-09-25T10:25:14.385Z

Link: CVE-2026-99008

Vulnrichment

No data.

NVD

Status : Received

Published: 2026-10-23T13:17:23.290

Modified: 2026-10-30T13:21:35.450

Link: CVE-2026-99008

Redhat

Severity : Moderate

Publid Date: 2026-10-23T00:00:00Z

Links: CVE-2026-99008 - Bugzilla

OpenCVE Enrichment

Updated: 2026-10-29T19:15:08Z

Weaknesses

CWE-476
NULL Pointer Dereference

Impact

Affected Systems

Risk and Exploitability

Tracking

Attack Vector Local

Attack Complexity High

Privileges Required High

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

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