CVE-2021-0920
MEDIUMCVE-2021-0920 is a medium-severity (CVSS 6.4) CWE-362 vulnerability. It is in CISA's Known Exploited Vulnerabilities catalog (added 2022-05-23) — treat it as actively exploited and patch now. No vendor fix is recorded yet; mitigation options are listed below.
Exploitation Status
Actively exploited in the wild
- Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2022-05-23. Federal agencies were required to remediate by 2022-06-13.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2021-0920.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2021-0920 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 394,415 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Description
In unix_scm_to_skb of af_unix.c, there is a possible use after free bug due to a race condition. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-196926917References: Upstream kernel
Affected Products
debian linuxdebianandroidgooglelinux kernellinuxResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
VulnerabilityDetect
Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).
Remediation status
No fixed release is recorded for CVE-2021-0920 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.
Mitigate without a patch
Constrain what reaches the vulnerable code: limit the size and shape of untrusted input, isolate the affected component in a sandboxed or least-privileged process, and enable the platform's memory-safety mitigations (ASLR, stack protector, hardened allocator) so an out-of-bounds access is more likely to fail closed than to be exploitable.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.Source: Red Hat security advisory for CVE-2021-0920 (CC BY 4.0)
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Enterprise Linux 6 Extended Lifecycle Support | kernel-0:2.6.32-754.47.1.el6 | RHSA-2022:1417 |
| Red Hat Enterprise Linux 7 | kernel-rt-0:3.10.0-1160.59.1.rt56.1200.el7 | RHSA-2022:0622 |
| Red Hat Enterprise Linux 7 | kpatch-patch | RHSA-2022:0592 |
| Red Hat Enterprise Linux 7 | kernel-0:3.10.0-1160.59.1.el7 | RHSA-2022:0620 |
| Red Hat Enterprise Linux 7.3 Advanced Update Support | kernel-0:3.10.0-514.99.1.el7 | RHSA-2022:1106 |
| Red Hat Enterprise Linux 7.4 Advanced Update Support | kernel-0:3.10.0-693.99.1.el7 | RHSA-2022:1104 |
| Red Hat Enterprise Linux 7.6 Advanced Update Support | kernel-0:3.10.0-957.92.1.el7 | RHSA-2022:1107 |
| Red Hat Enterprise Linux 7.6 Update Services for SAP Solutions | kpatch-patch | RHSA-2022:1103 |
Frequently Asked Questions
Is CVE-2021-0920 in your dependencies?
Find it across , including transitive dependencies.