CVE-2026-99008: Linux Vulnerability

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.

Metrics

EPSS Probability

0.17%

6.2th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= cad348a17e170451ea8688b532a6ca3e98c63b60, < b2b915042be073637d9f93dc51ef15fc0685ae8a; >= cad348a17e170451ea8688b532a6ca3e98c63b60, < a43452d8c1015ac2f0e43ff946be5425427b02cc; >= cad348a17e170451ea8688b532a6ca3e98c63b60, < 3f6394f6c6d1b6817065d3b402f55d437063a704; >= cad348a17e170451ea8688b532a6ca3e98c63b60, < d5c372ad03330f02962d4860df4d355ab25487df; >= cad348a17e170451ea8688b532a6ca3e98c63b60, < 3fd5164bdb04635caa7942ddb554b0ec699a9433; >= cad348a17e170451ea8688b532a6ca3e98c63b60, < a661f401f83b8462f2d424e0a1a72b7681e92ea2; >= cad348a17e170451ea8688b532a6ca3e98c63b60, < d0aef0b0374678153244f162df507106d728af39; >= cad348a17e170451ea8688b532a6ca3e98c63b60, < 08e90633377f1b2567ab5ad6810b74c552246a07
Linux	Linux	3.12

References

Timeline

Published: Oct 23, 2026
Last Modified: Oct 30, 2026
Status: Received

Frequently Asked Questions

What is CVE-2026-99008?

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.

How severe is CVE-2026-99008?

Severity scoring for CVE-2026-99008 is pending analysis. The EPSS model estimates a 0.17% probability of exploitation in the next 30 days.

How do I fix CVE-2026-99008?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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