CVE-2021-0920
MediumExploitedPublic exploitIn unix_scm_to_skb of af_unix.c, there is a possible use after free bug due to a race condition.
Published Mar 15, 2022 · Updated Oct 14, 2026 · Also known as A-196926917, ASB-A-196926917, DEBIAN-CVE-2021-0920, SUSE-SU-2022:0615-1, SUSE-SU-2022:0619-1, SUSE-SU-2022:0647-1, SUSE-SU-2022:0660-1, SUSE-SU-2022:0667-1, SUSE-SU-2022:0668-1, SUSE-SU-2022:0996-1, SUSE-SU-2022:1034-1, SUSE-SU-2022:1037-1, SUSE-SU-2022:1038-1, SUSE-SU-2022:1039-1, SUSE-SU-2022:1197-1, SUSE-SU-2022:1257-1, TR-22-0211, UBUNTU-CVE-2021-0920, USN-7720-1
Key Facts
Patch immediately- CVE-2021-0920 is a medium-severity vulnerability (CVSS 6.4 v3.1) affecting Debian Linux, Android (Google), Linux Kernel and 22 more products.
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Nov 5, 2021. Public exploit code is available.
- EPSS estimates a 0.9% probability of exploitation in the next 30 days.
- Fixed versions are available, including :linux_kernel: :2021-11-05, bpftool 3.10.0-1160.59.1.el7, bpftool 4.18.0-348.20.1.el8_5.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
6.4
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
0.9%
Higher than 57.9% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2021-0920 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
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
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | May 23, 2022 | Jun 13, 2022 | Not reported |
| Industry KEV feed | Nov 5, 2021 | Jun 13, 2022 | Not reported |
| CIRCL KEV | May 23, 2022 | Jun 13, 2022 | Not reported |
| ENISA EUVD | May 23, 2022 | n/a | Not reported |
Required action: Apply updates per vendor instructions.
Affected Products
1,192 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Debian LinuxDebian | 9.0 | n/a |
| AndroidGoogle | >= Android kernel | n/a |
| Linux KernelLinux | 5.14-rc1, 5.14-rc2, 5.14-rc3 | 5.13 |
| linuxdebian | See advisory | 5.10.70-1 |
| rootio-linuxrootio | See advisory | 5.10.70-1 |
Patched Releases
:linux_kernel:
:2021-11-05
bpftool
3.10.0-1160.59.1.el7, 4.18.0-348.20.1.el8_5
cluster-md-kmp-64kb
5.3.18-150300.59.60.4
cluster-md-kmp-azure
5.3.18-150300.38.50.1
cluster-md-kmp-default
4.12.14-122.106.1, 4.12.14-150.83.1, 4.12.14-197.105.1, 4.12.14-95.88.1, 4.4.180-94.156.1, 5.3.18-150200.24.112.1, 5.3.18-150300.59.60.4
cluster-md-kmp-preempt
5.3.18-150300.59.60.4
cluster-md-kmp-rt
4.12.14-10.73.1, 5.3.18-150200.79.2, 5.3.18-150300.82.1
dlm-kmp-64kb
5.3.18-150300.59.60.4
dlm-kmp-azure
5.3.18-150300.38.50.1
dlm-kmp-default
4.12.14-122.106.1, 4.12.14-150.83.1, 4.12.14-197.105.1, 4.12.14-95.88.1, 4.4.180-94.156.1, 5.3.18-150200.24.112.1, 5.3.18-150300.59.60.4
dlm-kmp-preempt
5.3.18-150300.59.60.4
dlm-kmp-rt
4.12.14-10.73.1, 5.3.18-150200.79.2, 5.3.18-150300.82.1
dtb-al
5.3.18-150300.59.60.4
dtb-allwinner
5.3.18-150300.59.60.4
dtb-altera
5.3.18-150300.59.60.4
dtb-amd
5.3.18-150300.59.60.4
dtb-amlogic
5.3.18-150300.59.60.4
dtb-apm
5.3.18-150300.59.60.4
dtb-arm
5.3.18-150300.59.60.4
dtb-broadcom
5.3.18-150300.59.60.4
dtb-cavium
5.3.18-150300.59.60.4
dtb-exynos
5.3.18-150300.59.60.4
dtb-freescale
5.3.18-150300.59.60.4
dtb-hisilicon
5.3.18-150300.59.60.4
dtb-lg
5.3.18-150300.59.60.4
Timeline
Added to Industry KEV feed
Nov 5, 2021
Publicly disclosed
Mar 15, 2022
Added to CISA KEV
May 23, 2022
Added to CIRCL KEV
May 23, 2022
Added to ENISA EUVD
May 23, 2022
Last updated
Oct 14, 2026
Weakness Type
- CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
- CWE-416 Use After Free
References
- advisoryhttp://access.redhat.com/errata/RHSA-2022:0824
- advisoryhttp://bugzilla.redhat.com/show_bug.cgi?id=2044561
- advisoryhttp://dirtypipe.cm4all.com/
- advisoryRHSA-2022:0590
- advisoryRHSA-2022:0592
FAQ
Common Questions.
In unix_scm_to_skb of af_unix.c, there is a possible use after free bug due to a race condition.
Affected: Debian Linux versions 9.0; Android (Google) versions >= Android kernel; Linux Kernel versions 5.14-rc1, 5.14-rc2, 5.14-rc3, among others. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Nov 5, 2021.
Yes. It was added on May 23, 2022 with a federal remediation due date of Jun 13, 2022.
Public exploit code is available.
Fixed versions are available, including :linux_kernel: :2021-11-05, bpftool 3.10.0-1160.59.1.el7, bpftool 4.18.0-348.20.1.el8_5.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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