CVE-2021-20194: There is a vulnerability in the linux kernel versions higher than 5.2 (if kernel compiled with config params CONFIG_BPF_SYSCALL=y CONFIG_BPF=y CONFIG_CGROUPS=y CONFIG_CGROUP_BPF=y CONFIG_HARDENED_USERCOPY not set and BPF hook to getsockopt is registered). As result of BPF execution the local user can trigger bug in __cgroup_bpf_run_filter_getsockopt() function that can lead to heap overflow (because of non-hardened usercopy). The impact of attack could be deny of service or possibly privileges escalation.

Overview

Severity: High (CVSS 7.8)
CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Exploit Status: Not Exploited
Patch Tuesday: 2021-Feb
Released: 2021-02-27
Last Updated: 2026-02-19
EPSS Score: 0.05% (percentile: 15.6%)

FAQ

Is Azure Linux the only Microsoft product that includes this open-source library and is therefore potentially affected by this vulnerability? One of the main benefits to our customers who choose to use the Azure Linux distro is the commitment to keep it up to date with the most recent and most secure versions of the open source libraries with which the distro is composed. Microsoft is committed to transparency in this work which is why we began publishing CSAF/VEX in October 2025. See this blog post for more information. If impact to additional products is identified, we will update the CVE to reflect this.

Overview

FAQ

Affected Products (3)

Other

Revision History