CVE-2026-99009: Linux kernel · Bluetooth: RFCOMM: connect the session socket without rfcomm_mutex
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 28 Oct 2026, 01:58 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
Exploitation evidence
Disclosed: evidence found.
CVE published 23 Oct 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
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10linuxpkg:deb/ubuntu/linux?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-oraclepkg:deb/ubuntu/linux-oracle?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix for this vulnerability is available and should be applied. The patch modifies the locking order during RFCOMM session socket connection to remove the circular dependency and adds safeguards for race conditions involving session sockets and DLCs. Users should update to patched Linux kernel versions that include this fix. No additional mitigation actions are required beyond applying the official patch.
Description
CVE-2026-99009 is a Linux kernel vulnerability in the Bluetooth RFCOMM subsystem involving improper locking order during session socket connection. The flaw causes a circular locking dependency between rfcomm_mutex and hdev->lock, which can lead to lockdep warnings and potential race conditions. The issue arises when an RFCOMM connect() call is made while a BR/EDR link is authenticating, resulting in inconsistent lock acquisition order. The fix involves changing the connection sequence to connect the session socket before acquiring rfcomm_mutex, eliminating the circular dependency and handling edge cases where sockets or DLCs may be closed during connection.
References
- ubuntu.com/security/CVE-2026-99009 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-99009 (opens in a new tab)
- git.kernel.org/stable/c/4dc3d5a004b8fd59f3c905631dbb18cb601b1b41 (opens in a new tab)
- git.kernel.org/stable/c/ac022970e9fb0a5f7e7d1f6c8e104c1ed924dd1c (opens in a new tab)
- git.kernel.org/stable/c/cc7732b8549ecb6f02457edeb8db1f6d255e381c (opens in a new tab)
- git.kernel.org/stable/c/d2206e8c78be69d21d4f5343c3e99fbaeef41cbb (opens in a new tab)
- git.kernel.org/stable/c/f492de11b325446b0b11bc2eb86e1f546eaa61b6 (opens in a new tab)