CVE-2021-4001

low-risk
Published 2022-01-21

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.

Do I need to act?

-
0.02% chance of exploitation
EPSS score — low exploit probability
-
Not on CISA KEV list
No confirmed active exploitation reported to CISA
?
Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
4
CVSS 4.1/10 Medium
LOCAL / HIGH complexity

Affected Products (2)

Affected Vendors

Linux

References (4)

Issue Tracking https://bugzilla.redhat.com/show_bug.cgi?id=2025645
Patch https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git/commit/?id=353050be4...
Issue Tracking https://bugzilla.redhat.com/show_bug.cgi?id=2025645
Patch https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git/commit/?id=353050be4...
18
/ 100
low-risk
Severity 11/34 · Low
Exploitability 0/34 · Minimal
Exposure 7/34 · Low