Use-after-free in Linux kernel - CVE-2021-47209
Published: May 31, 2024 / Updated: May 14, 2025
Vulnerability identifier: #VU90207
CSH Severity: Low
CVSSv4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2021-47209
CWE-ID: CWE-416
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerable software:
Linux kernel
Linux kernel
Software vendor:
Linux Foundation
Linux Foundation
Description
The vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to a use-after-free error within the rq_of_rt_se() and rt_rq_of_se() functions in kernel/sched/rt.c, within the free_fair_sched_group() and unregister_fair_sched_group() functions in kernel/sched/fair.c, within the sched_free_group(), sched_online_group(), cpu_cgroup_css_released() and cpu_cgroup_css_free() functions in kernel/sched/core.c, within the autogroup_destroy() function in kernel/sched/autogroup.c. A local user can escalate privileges on the system.
Remediation
Install update from vendor's website.