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CVE-2021-22600

Double Free in net/packet/af_packet.c leading to priviledge escalation

  • Medium 6.6
  • Exploited: added to CISA KEV 11 Apr 2022

Description

A double free bug in packet_set_ring() in net/packet/af_packet.c can be exploited by a local user through crafted syscalls to escalate privileges or deny service. We recommend upgrading kernel past the effected versions or rebuilding past ec6af094ea28f0f2dda1a6a33b14cd57e36a9755

Key facts

Published
26 Jan 2022
Last changed
21 Oct 2025
Assigned by
Google
KEV added
11 Apr 2022
KEV fix due
2 May 2022
EPSS
6.586% likely to be exploited in the next 30 days, higher than 93.941% of CVEs (scores for 15 Nov 2026)
SSVC (CISA)
Exploitation: active; Automatable: no; Technical impact: partial

Severity scores

Each score is shown as its source gave it. They are not averaged or merged.

  • 6.6CVSS 3.1, Mediumfrom the CNA (Google)CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:H

What to do

  • Apply updates per vendor instructions.CISA KEV required action

Historical context and remediation

This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.

No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.

Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.

Read the original CVE record.

Affected products

VendorProductVersions
Linux KernelKernel
  • unspecified up to but excluding 5.4.168 (affected)
  • unspecified up to but excluding 5.10.88 (affected)
  • unspecified up to but excluding 5.15.11 (affected)
  • unspecified up to but excluding 5.16-rc6 (affected)

Timeline

  1. 26 Jan 2022 Published
  2. 11 Apr 2022 CVE-2021-22600 added to CISA KEV
  3. 11 Apr 2022 Added to the CISA KEV catalogue

Weakness

References