CVE-2021-4001

Public on 2022-01-06

Modified on 2022-01-06

Description

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.

Severity

Medium

See what this means

CVSS v3 Base Score

6.7

See breakdown

Affected Packages

Platform	Package	Release Date	Advisory
Amazon Linux 2 - Kernel-5.10 Extra	kernel	2024-02-01 20:10	ALAS2KERNEL-5.10-2024-049
Amazon Linux 2 - Kernel-5.10 Extra	kernel	2022-01-21 00:04	ALAS2KERNEL-5.10-2022-008
Amazon Linux 2 - Kernel-5.4 Extra	kernel	2022-01-20 19:13	ALAS2KERNEL-5.4-2022-010
Amazon Linux 2 - Kernel-5.4 Extra	kernel	2025-01-31 05:43	ALAS2KERNEL-5.4-2025-093

CVSS Scores

	Score Type	Score	Vector
Amazon Linux	CVSSv3	6.7	CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
NVD	CVSSv2	4.7	AV:L/AC:M/Au:N/C:N/I:C/A:N
NVD	CVSSv3	4.1	CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:H/A:N

References

Red Hat: CVE-2021-4001 Mitre: CVE-2021-4001 FAQs regarding Amazon Linux ALAS/CVE Severity