How severe is CVE-2021-0920?

CVE-2021-0920 has a CVSS 3.x base score of 6.4, rated medium severity. It is exploitable over local access with high attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-0920 being actively exploited?

Yes. CVE-2021-0920 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2022-05-23, which means active exploitation has been confirmed. It should be prioritised for remediation.

What products are affected by CVE-2021-0920?

CVE-2021-0920 primarily affects Linux Linux Kernel. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-0920?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.

Does CVE-2021-0920 have an EU (EUVD) identifier?

Yes. CVE-2021-0920 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-3539. It is also flagged as exploited in the EUVD (since 2022-05-23).

When was CVE-2021-0920 published?

CVE-2021-0920 was published on 2021-12-15 and last updated on 2026-06-17.

CVE-2021-0920

CVE-2021-0920 is a medium-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 6.4. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2022-05-23). The underlying weakness is classified as CWE-362.

Key facts

Severity: Medium (CVSS 3.x base score 6.4)
CVSS v2: 6.9
EPSS exploit prediction: 1% (53rd percentile)
Actively exploited: Yes — listed in CISA KEV (added 2022-05-23)
EU (EUVD) id: EUVD-2021-3539
EU exploitation: Flagged exploited in the ENISA EU Vulnerability Database (since 2022-05-23)
Weakness: CWE-362
Affected product: Linux Linux Kernel
Published: 2021-12-15
Last modified: 2026-06-17

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

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
How severe is CVE-2021-0920?: CVE-2021-0920 has a CVSS 3.x base score of 6.4, rated medium severity. It is exploitable over local access with high attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-0920 being actively exploited?: Yes. CVE-2021-0920 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2022-05-23, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2021-0920?: CVE-2021-0920 primarily affects Linux Linux Kernel. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-0920?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2021-0920 have an EU (EUVD) identifier?: Yes. CVE-2021-0920 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-3539. It is also flagged as exploited in the EUVD (since 2022-05-23).
When was CVE-2021-0920 published?: CVE-2021-0920 was published on 2021-12-15 and last updated on 2026-06-17.

References

Affected products (6)

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.14:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.14:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.14:rc3:*:*:*:*:*:*
cpe:2.3:o:google:android:-:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*

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