CVE-2021-20194 Memory corruption in kernel
A local attacker can trigger a heap overflow in the Linux kernel BPF subsystem, potentially leading to privilege escalation or denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2021-20194?
CVE-2021-20194 is a high-severity memory corruption vulnerability in Linux kernel, published on 23 Feb 2021. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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.
Which versions are affected by CVE-2021-20194?
It affects 3 products.
Products include Linux kernel, Redhat Enterprise Linux, Redhat Openshift Container Platform.
How do I fix CVE-2021-20194?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2021-20194 being exploited?
There is no known exploitation of CVE-2021-20194 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-34857, AZL-6529, DEBIAN-CVE-2021-20194, GHSA-vw35-vgjr-5jhv, UBUNTU-CVE-2021-20194.