Race Condition in Linux Kernel's ebpf Verifier Allows Unauthorized Modification of Frozen Mapped Address Space

CVE-2021-4001 · MEDIUM Severity

CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:H/A:N

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.

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