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CVE

CVE-2021-0920

Android Kernel Race Condition Vulnerability

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.

MEDIUM · CVSS 6.4 ⚠ CISA KEV EPSS 0.00933
Act now
  • Listed on CISA KEV (known exploited in the wild)
  • SSVC exploitation status: active
Sigma rules0 YARA rules0
⬢

Required Remediation

Apply updates per vendor instructions.

⬡

Weakness Classification

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

Affected Products & Versions

4
linux kernel<= 5.13
linux kernelall versions
google androidall versions
debian linuxall versions
▣

Scoring & Timeline

6.4
MEDIUM · CVSS v3.1 · security@android.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD15 Dec 2021 · 07:15 PM
CVSS VectorCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
SSVC triage · cisa-vulnrichment
Exploitation
active
Automatable
no
Technical impact
total
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
⚑

Vendor Advisories

30
suse-csafSUSE-SU-2026:0688-1
usnUSN-7720-1
rhsaRHSA-2022:0777Moderate
siemens-csafSSA-770721
cisaKEV-CVE-2021-0920
🔗

References & Sources

3
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://lists.debian.org/debian-lts-announce/2021/12/msg00012.htmlMailing ListThird Party Advisory
https://source.android.com/security/bulletin/2021-11-01Vendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-0920Third Party AdvisoryUS Government Resource
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