01 Record

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

MediumKEVPUBLISHEDCNA: google_android

CNA base score6.4 CVSS v3.xCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H

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02 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

03 Exploitation and scoring

Exploitation

Exploited in the wild. Listed in the CISA Known Exploited Vulnerabilities catalog on 2022-05-23. Federal remediation due 2022-06-13.

SSVC decision

ExploitationactiveCISA reports credible evidence of active exploitation.
AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

0.86% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 58.5% of scored records. A rank, not a probability.

NVD base score

6.4 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H

NVD analysis status

Analyzed. NVD last modified this record on 2026-06-17.

Red Hat severity

Important. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published

2021-12-15 18:05Z4 YR AGO

Last updated

2025-10-21 23:15Z1 YR AGO

Reserved

2020-11-06

Assigning CNA

google_android

Record state

PUBLISHED

Severity

Medium (CVSS 6.4)

CNA CVSS vector

CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H

Weaknesses

CWE-416Use After FreeVariant
CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')Class

Data version

5.1

Document digest

33b9968a71867a8655e059b31230cdbda5ee275f249dcc36a3fd8c3bb97ac8c6

05 Affected products

VendorProductVersionsPlatforms

n/aAndroidAndroid kernel—

06 References

source.android.comhttps://source.android.com/security/bulletin/2021-11-01x_refsource_MISC
lists.debian.org[debian-lts-announce] 20211216 [SECURITY] [DLA 2843-1] linux security updatehttps://lists.debian.org/debian-lts-announce/2021/12/msg00012.htmlmailing-listx_refsource_MLIST
www.cisa.govhttps://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-0920government-resource

07 Fixed in

AlmaLinux 8

kernel-tools-libs-devel
Fixed in 4.18.0-348.20.1.el8_5

CloudLinux 8

kernel-tools-libs-devel
Fixed in 4.18.0-348.20.1.el8_5

Derived from AlmaLinux 8. Partial coverage: only packages taken from AlmaLinux 8 are listed.

Debian 12

linux
Fixed in 5.14.6-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 13

linux
Fixed in 5.14.6-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 14

linux
Fixed in 5.14.6-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.