Vulnerability · Published Jan 21, 2022 · Assigned by redhat
CVE-2021-4001
Medium 4.1
In plain English
A medium-severity security flaw in kernel. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 8% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS NVD)4.1Medium
Exploit odds (30 days)0.2%top 91.7% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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. This flaw affects kernel versions prior to 5.16 rc2.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | linux | 5.15.5-1 | DEBIAN-CVE-2021-4001 |
| Debian:13 | linux | 5.15.5-1 | DEBIAN-CVE-2021-4001 |
| Debian:14 | linux | 5.15.5-1 | DEBIAN-CVE-2021-4001 |
| Ubuntu:22.04:LTS | linux-intel-iot-realtime | no fix listed | UBUNTU-CVE-2021-4001 |
| Ubuntu:24.04:LTS | linux-raspi-realtime | no fix listed | UBUNTU-CVE-2021-4001 |
| Ubuntu:22.04:LTS | linux-realtime | no fix listed | UBUNTU-CVE-2021-4001 |
Affected products (as reported)
Weakness: CWE-367