---
id: "CVE-2021-22600"
kind: "vulnerability"
aliases: ["CVE-2021-22600"]
title: "Linux Kernel: Linux Kernel Privilege Escalation Vulnerability"
severity: "high"
cvss: 7.2
epss: 0.06586
exploited: true
status: "open"
category: "infrastructure"
products: [{"name": "Linux Kernel", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["exploited", "infrastructure", "kubernetes", "linux", "self-hosted"]
not_affected_if: ["no-local-untrusted-users", "patched-kernel"]
published_at: "2022-01-26T14:15:08+00:00"
first_seen_at: "2026-10-23T19:11:52+00:00"
updated_at: "2026-10-23T21:57:35+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-22600", "first_seen_at": "2026-10-23T19:11:52+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2021-22600", "first_seen_at": "2026-10-23T19:13:44+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-22600", "first_seen_at": "2026-10-23T21:57:35+00:00"}]
---

# Linux Kernel: Linux Kernel Privilege Escalation Vulnerability

The Linux kernel's packet socket (AF_PACKET) code can free memory incorrectly. A local user can crash the machine or possibly gain root.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Linux Kernel affected ? fixed ?

## How to check

uname -r

## Fix

Update the kernel to a vendor release that includes the fix for CVE-2021-22600, then reboot. Exact fixed version: unknown

## Timeline

- 2026-10-23T19:11:52+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-22600
- 2026-10-23T19:13:44+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2021-22600
- 2026-10-23T21:57:35+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2021-22600

## From the sources

Linux Kernel contains a flaw in the packet socket (AF_PACKET) implementation which could lead to incorrectly freeing memory. A local user could exploit this for denial-of-service (DoS) or possibly for privilege escalation.

CISA required action: Apply updates per vendor instructions.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_