cbcvebase.
CVE-2025-21902
published 2025-04-01

CVE-2025-21902: In the Linux kernel, the following vulnerability has been resolved: acpi: typec: ucsi: Introduce a ->poll_cci method For the ACPI backend of UCSI the UCSI…

PriorityP419medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
EPSS
0.19%
9.4th percentile
In the Linux kernel, the following vulnerability has been resolved: acpi: typec: ucsi: Introduce a ->poll_cci method For the ACPI backend of UCSI the UCSI "registers" are just a memory copy of the register values in an opregion. The ACPI implementation in the BIOS ensures that the opregion contents are synced to the embedded controller and it ensures that the registers (in particular CCI) are synced back to the opregion on notifications. While there is an ACPI call that syncs the actual registers to the opregion there is rarely a need to do this and on some ACPI implementations it actually breaks in various interesting ways. The only reason to force a sync from the embedded controller is to poll CCI while notifications are disabled. Only the ucsi core knows if this is the case and guessing based on the current command is suboptimal, i.e. leading to the following spurious assertion splat: WARNING: CPU: 3 PID: 76 at drivers/usb/typec/ucsi/ucsi.c:1388 ucsi_reset_ppm+0x1b4/0x1c0 [typec_ucsi] CPU: 3 UID: 0 PID: 76 Comm: kworker/3:0 Not tainted 6.12.11-200.fc41.x86_64 #1 Hardware name: LENOVO 21D0/LNVNB161216, BIOS J6CN45WW 03/17/2023 Workqueue: events_long ucsi_init_work [typec_ucsi] RIP: 0010:ucsi_reset_ppm+0x1b4/0x1c0 [typec_ucsi] Call Trace: ucsi_init_work+0x3c/0xac0 [typec_ucsi] process_one_work+0x179/0x330 worker_thread+0x252/0x390 kthread+0xd2/0x100 ret_from_fork+0x34/0x50 ret_from_fork_asm+0x1a/0x30 Thus introduce a ->poll_cci() method that works like ->read_cci() with an additional forced sync and document that this should be used when polling with notifications disabled. For all other backends that presumably don't have this issue use the same implementation for both methods.

Affected

11 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 6.12.19-1 (forky)linux 6.12.19-1 (forky)
linuxlinux
linuxlinux>= 6.12.5 < 6.12.196.12.19
linuxlinux>= c0ca6fd5f6ebde8fc0df8bb5c32629d1284f60d0 < 012b98cdb54c7d47743ee7fc402fa23f2d90529a012b98cdb54c7d47743ee7fc402fa23f2d90529a
linuxlinux>= fa48d7e81624efdf398b990a9049e9cd75a5aead < 1aec5c9066965ac0984e385bbc31455ae31cbffc1aec5c9066965ac0984e385bbc31455ae31cbffc
linuxlinux>= fa48d7e81624efdf398b990a9049e9cd75a5aead < 976e7e9bdc7719a023a4ecccd2e3daec9ab20a40976e7e9bdc7719a023a4ecccd2e3daec9ab20a40
linuxlinux_kernel
linuxlinux_kernel>= 0 < 6.12.19-16.12.19-1
linuxlinux_kernel>= 0 < 6.12.19-16.12.19-1
linuxlinux_kernel>= 6.12.5 < 6.12.196.12.19
linuxlinux_kernel>= 6.13 < 6.13.76.13.7

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
osv5.9MEDIUM
vendor_ubuntu5.9MEDIUM
vendor_debian5.5LOW
vendor_redhat5.5MEDIUM
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