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ExploitedIn CISA KEVFix available

CVE-2021-0920

Exploitation confirmed. First attested on 2022-05-23 by CISA-ADP, CISA KEV, GCVE · kevintel.

  • Published2021-12-15
  • WeaknessCWE-362 · CWE-416

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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

Timeline

dates in UTC
  1. 2021-12-1519:15CVE publishedNVD
  2. 2022-05-23Added to the CISA KEV catalogCISA KEV
  3. 2022-05-23Listed as exploited by GCVEGCVE
  4. 2022-05-23Exploitation first reportedCISA KEV
  5. 2024-02-0616:18SSVC exploitation set to activeCISA-ADP

Observed activity

isMalicious corpus · updated 2026-11-03 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-0920?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-0920?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Linux linux kernel
BranchAffectedFixed in
5.13≤ 5.13no fix published
5.14= 5.14no fix published
Debian debian linux
BranchAffectedFixed in
9.0= 9.0no fix published
Google android
BranchAffectedFixed in
—all versionsno fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA1 product

As google_android, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • Android
    Affected
    • = Android kernelno fix stated

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2021-12-17

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • :linux_kernel:Androidfrom :0 · fixed in :2021-11-05
  • dtb-aarch64openSUSE:Leap 15.3all versions · fixed in 5.3.18-150300.59.60.4and 11 other packages
  • kernelTuxCare:CentOS:8.5all versions · fixed in 4.18.0-348.7.1.el8_5.tuxcare.els7and 21 other packages
  • kernelTuxCare:CentOS:8.4all versions · fixed in 4.18.0-305.25.1.el8_4.tuxcare.els7and 21 other packages
  • kernelTuxCare:CentOS:6all versions · fixed in 2.6.32-754.35.8.el6.tuxcare.els10and 9 other packages
  • kernelRocky Linux:8all versions · fixed in 0:4.18.0-348.20.1.el8_5
  • kernelRed Hat:rhel_eus:8.4::baseosall versions · fixed in 0:4.18.0-305.40.1.el8_4and 32 other packages
  • kernelRed Hat:rhel_eus:8.2::baseosall versions · fixed in 0:4.18.0-193.75.1.el8_2and 32 other packages

221 more package ranges on OSV.dev

Vendor advisories

  • CVE-2021-0920 Red Hat Product Security1,364 products fixed

    kernel: Use After Free in unix_gc() which could result in a local privilege escalation

  • ICSA-24-074-07 CISA1 known affected

    Siemens SIMATIC

    Siemens SIMATIC RF160B (6GT2003-0FA00): <V2.2

  • SSA-770721 Siemens ProductCERT1 known affected

    SSA-770721: Multiple Vulnerabilities in SIMATIC RF160B before V2.2

    SIMATIC RF160B (6GT2003-0FA00)

  • RHSA-2022:1417 Red Hat Product Security56 products fixed

    Red Hat Security Advisory: kernel security update

  • RHSA-2022:1373 Red Hat Product Security40 products fixed

    Red Hat Security Advisory: kpatch-patch security update

  • RHSA-2022:1324 Red Hat Product Security106 products fixed

    Red Hat Security Advisory: kernel security and bug fix update

21 more advisories

Full record on NVD

Fix

  1. CISA’s required action: Apply updates per vendor instructions.due 2022-06-13
  2. Vendor fix Siemens ProductCERT SSA-770721 · 1 productUpdate to V2.2 or later version
  3. Vendor fix Red Hat Product Security RHSA-2022:1417 · 56 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 The system must be rebooted for this update to take effect.
  4. Vendor fix Red Hat Product Security RHSA-2022:1373 · 40 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
  5. Vendor fix Red Hat Product Security RHSA-2022:1263 · 4 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/2974891
  6. Workaround from the vendor Red Hat Product Security RHSA-2022:1417 · 56 productsMitigation 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.
  7. Mitigation from the vendor CISA ICSA-24-074-07 · 1 productSiemens has released a new version (V2.2) for SIMATIC RF160B and recommends to update to the latest version.

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub
Metasploit modules
none listed
Metasploit Framework

CISA Known Exploited Vulnerability

Date Added
2022-05-23
Patch Due Date
2022-06-13
Ransomware Use
Unknown
Required Action
Apply updates per vendor instructions.

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
Published
2021-12-15
Last Modified
2026-06-17
NVD status
Analyzed
GitHub Advisory
GHSA-r93f-j2vf-vmc4

Frequently asked questions

What is CVE-2021-0920?

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

Is CVE-2021-0920 actively exploited?

Yes. CVE-2021-0920 is on the CISA Known Exploited Vulnerabilities (KEV) catalog, meaning it has been confirmed as actively exploited in the wild. CISA requires federal agencies to patch by 2022-06-13.

What is the CVSS score for CVE-2021-0920?

CVE-2021-0920 has a CVSS v3 base score of 6.4 (MEDIUM severity), with vector string CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H.

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