Vulnerability in Linux Kernel
CVE-2021-4001
A race condition was found in the Linux kernel's ebpf verifier between bpf_map_update_elem and bpf_map_freeze due to a missing lock in kernel/bpf/syscall.c. In this flaw, a local user with a special privilege (cap_sys_admin or cap_bpf) can modify the frozen mapped address space. This flaw affects kernel versions prior to 5.16 rc2.
Vulnerability class: TOCTOU (Time-of-Check to Time-of-Use)
EPSS: 0.002 (8.5th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 4.1 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:H/A:N.
Affected products
- Linux Linux_kernel — versions 5.16
- N/a Kernel — versions kernel 5.16 rc2
Weakness classification (CWE)
References
- secalert@redhat.com (Patch, Third Party Advisory, Issue Tracking)
- secalert@redhat.com (Patch, Third Party Advisory)
Frequently asked questions
- What is CVE-2021-4001?
- CVE-2021-4001 is a medium-severity vulnerability in Linux Kernel, classified under Time-of-check Time-of-use (TOCTOU) Race Condition. CVSS score: 4.1/10. Published 2022-01-21.
- How severe is CVE-2021-4001?
- Medium severity. CVSS v3 base score is 4.1 out of 10.