Linux · Linux Kernel · CVE-2021-38200
**Name of the Vulnerable Software and Affected Versions**
Linux kernel versions prior to 5.12.13
**Description**
The issue is related to a NULL pointer dereference in the arch/powerpc/perf/core-book3s.c file of the Linux kernel. This can be exploited by local users to cause a denial of service (perf instruction pointer NULL pointer dereference and OOPS) via a "perf record" command, on systems with perf event paranoid=-1 and no specific PMU driver support registered.
**Recommendations**
For Linux kernel versions prior to 5.12.13, update to version 5.12.13 or later to resolve the issue. As a temporary workaround, consider restricting access to the "perf record" command to minimize the risk of exploitation. Additionally, setting perf event paranoid to a value other than -1 may also help mitigate the risk.