CVE-2025-21902

CVE Details

Release Date:	2025-04-01
Impact:	Low	What is this?

Description

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.

See more information about CVE-2025-21902 from MITRE CVE dictionary and NIST NVD

NOTE: The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 metrics

Base Score:	5.5
Vector String:	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Version:	3.1
Attack Vector:	Local
Attack Complexity:	Low
Privileges Required:	Low
User Interaction:	None
Scope:	Unchanged
Confidentiality Impact:	None
Integrity Impact:	None
Availability Impact:	High

Errata information

Platform	Errata	Release Date
Oracle Linux version 10 (kernel-uek)	ELSA-2025-20480	2025-07-17
Oracle Linux version 9 (kernel-uek)	ELSA-2025-20480	2025-07-17