#VU105148 Improper locking in Linux kernel - CVE-2025-21820
Vulnerability identifier: #VU105148
Vulnerability risk: Low
CVSSv4.0: 4.3 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]
CVE-ID: CVE-2025-21820
CWE-ID:
CWE-667
Exploitation vector: Local
Exploit availability: No
Vulnerable software:
Linux kernel
Operating systems & Components /
Operating system
Vendor: Linux Foundation
Description
The vulnerability allows a local user to perform a denial of service (DoS) attack.
The vulnerability exists due to improper locking within the cdns_uart_handle_rx(), cdns_uart_isr() and cdns_uart_console_write() functions in drivers/tty/serial/xilinx_uartps.c. A local user can perform a denial of service (DoS) attack.
Mitigation
Install update from vendor's website.
Vulnerable software versions
Linux kernel: All versions
External links
https://git.kernel.org/stable/c/4410dba9807a17a93f649a9f5870ceaf30a675a3
https://git.kernel.org/stable/c/8ea0e7b3d7b8f2f0fc9db491ff22a0abe120801c
https://git.kernel.org/stable/c/9b88a7c4584ba67267a051069b8abe44fc9595b2
https://git.kernel.org/stable/c/b06f388994500297bb91be60ffaf6825ecfd2afe
https://git.kernel.org/stable/c/de5bd24197bd9ee37ec1e379a3d882bbd15c5065
Q & A
Can this vulnerability be exploited remotely?
No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
