CVE-2026-89569
HighCVSS 8.8Exploitation Probability (EPSS)
Low risk26th percentile - higher than 26% of all known CVEs
Summary
A use-after-free vulnerability exists in the Linux kernel's rfcomm_security_cfm() function in the Bluetooth RFCOMM subsystem. The function walks the session and DLC lists without holding rfcomm_mutex, allowing the krfcommd thread to concurrently free the same session and its DLCs. This results in a read of freed memory (KASAN: slab-use-after-free).
Risk Assessment
The vulnerability can cause a kernel panic or potentially allow code execution in kernel context, threatening system confidentiality, integrity, and availability. It affects systems with active Bluetooth RFCOMM.
Recommendation
Update the Linux kernel to a version containing the fix that serializes rfcomm_security_cfm() handling with rfcomm_mutex. If updating is not possible, consider disabling Bluetooth or restricting RFCOMM usage.
Other vulnerabilities in Linux kernel
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- CVE-2026-99258Unknown
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- CVE-2026-99257Unknown
In the Linux kernel, the shared GPIO mechanism based on platform lookup tables requires an associated struct device. An fwnode-based lookup with no associated device currently causes a NULL-pointer dereference. The fix adds a check that lets the kernel gracefully handle this situation with an error.
- CVE-2026-99256Unknown
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- CVE-2026-99251Unknown
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- CVE-2026-99250Unknown
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- CVE-2026-99248Unknown
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- CVE-2026-99247Unknown
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In the Linux kernel power supply subsystem, a use-after-free vulnerability exists. If a power supply is unregistered while its external_power_changed() callback is still running, the driver may free data that the callback is still accessing, leading to a kernel crash (NULL pointer dereference).
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: RFCOMM: serialize security confirmation handling rfcomm_security_cfm() looks up a session on session_list and then walks its DLC list without holding rfcomm_mutex. Since RFCOMM session teardown uses rfcomm_mutex, krfcommd can close and free the same session and DLCs concurrently: hci_rx_work krfcommd ----------- --------- rfcomm_session_get() rfcomm_lock() rfcomm_session_close() rfcomm_dlc_unlink() rfcomm_session_del() kfree(s) rfcomm_unlock() walk s->dlcs The callback can then read a freed session list head and touch freed DLCs while updating their flags or timers. Serialize the session lookup and DLC traversal in rfcomm_security_cfm() with rfcomm_mutex. This matches the existing RFCOMM session lifetime rules and prevents concurrent rfcomm_session_del() / rfcomm_dlc_unlink() from tearing the objects down while the callback is using them. KASAN reported: BUG: KASAN: slab-use-after-free in rfcomm_security_cfm+0x41c/0x440 Read of size 8 at addr ffff888111fb3960 by task kworker/u17:1/89 Workqueue: hci0 hci_rx_work Call Trace: rfcomm_security_cfm+0x41c/0x440 hci_encrypt_cfm+0x139/0x590 hci_encrypt_change_evt+0x37b/0xc40 hci_event_packet+0x71b/0xb20 hci_rx_work+0x293/0x730 Allocated by task 69: rfcomm_session_add+0x9e/0x2f0 rfcomm_run+0x44b/0x41e0 Freed by task 69: kfree+0x131/0x3c0 rfcomm_session_del+0x188/0x220 rfcomm_run+0x1985/0x41e0
Vulnerability data from NVD (NIST) · CISA KEV · EPSS

