CVE-2025-21820

CVSS v3 Score
5.5
Medium

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: tty: xilinx_uartps: split sysrq handling lockdep detects the following circular locking dependency: CPU 0 CPU 1 ========================== ============================ cdns_uart_isr() printk() uart_port_lock(port) console_lock() cdns_uart_console_write() if (!port->sysrq) uart_port_lock(port) uart_handle_break() port->sysrq = ... uart_handle_sysrq_char() printk() console_lock() The fixed commit attempts to avoid this situation by only taking the port lock in cdns_uart_console_write if port->sysrq unset. However, if (as shown above) cdns_uart_console_write runs before port->sysrq is set, then it will try to take the port lock anyway. This may result in a deadlock. Fix this by splitting sysrq handling into two parts. We use the prepare helper under the port lock and defer handling until we release the lock.

CVSS:5.5(Medium)

Concurrent Versions Software (CVS) uses predictable temporary file names for locking, which allows local users to cause a denial of service by creating the lock directory before it is created for use ...

CVSS:5.5(Medium)

qpopper POP server creates lock files with predictable names, which allows local users to cause a denial of service for other users (lack of mail access) by creating lock files for other mail boxes.

CVSS:5.5(Medium)

ZoneAlarm and ZoneAlarm Pro allows a local attacker to cause a denial of service by running a trojan to initialize a ZoneAlarm mutex object which prevents ZoneAlarm from starting.

CVSS:5.5(Medium)

dump 0.4 b10 through b29 allows local users to cause a denial of service (execution prevention) by using flock() to lock the /etc/dumpdates file.

CVSS:5.5(Medium)

tip on multiple BSD-based operating systems allows local users to cause a denial of service (execution prevention) by using flock() to lock the /var/log/acculog file.

CVSS:5.5(Medium)

Array index overflow in the xfrm_sk_policy_insert function in xfrm_user.c in Linux kernel 2.6 allows local users to cause a denial of service (oops or deadlock) and possibly execute arbitrary code via...