{"id":"CVE-2021-22600","kind":"vulnerability","aliases":["CVE-2021-22600"],"related":[],"title":"Linux Kernel: Linux Kernel Privilege Escalation Vulnerability","description":"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.\n\nCISA required action: Apply updates per vendor instructions.","summary":"The Linux kernel's packet socket (AF_PACKET) code can free memory incorrectly. A local user can crash the machine or possibly gain root.","severity":"high","cvss":7.2,"epss":0.06586,"exploited":true,"exploited_at":"2022-04-11T00:00:00+00:00","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"],"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","status":"open","published_at":"2022-01-26T14:15:08+00:00","first_seen_at":"2026-10-23T19:11:52+00:00","triaged_at":"2026-10-23T21:18:02+00:00","updated_at":"2026-10-23T21:57:35+00:00","category":"infrastructure","confidence":0.7,"triage":{"at":"2026-10-23T21:18:02Z","model":"claude-haiku-5-5","output":{"fix":"Update the kernel to a vendor release that includes the fix for CVE-2021-22600, then reboot. Exact fixed version: unknown","reach":"local","impact":"high","summary":"The Linux kernel's packet socket (AF_PACKET) code can free memory incorrectly. A local user can crash the machine or possibly gain root.","category":"infrastructure","who_cares":["linux","self-hosted","kubernetes"],"confidence":0.7,"needs_auth":"yes","worst_case":"local user gains kernel privileges or crashes the host","analyst_note":"Confirm fixed kernel versions per distro from the vendor advisories; CISA KEV lists it as known exploited, so check the KEV entry for the remediation deadline.","how_to_check":"uname -r\nunknown","needs_analyst":true,"not_affected_if":["patched-kernel","no-local-untrusted-users"],"user_interaction":"no","needs_special_setup":"no","severity_if_unknown":"high"},"cost_usd":0.000458,"input_tokens":2854,"output_tokens":345,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2021':9A,12A '-22600':10A,13A 'action':85C 'af':29B,56C 'appli':86C 'cisa':83C 'code':31B 'contain':49C 'could':60C,69C 'crash':40B 'cve':8A,11A 'denial':74C 'denial-of-servic':73C 'dos':77C 'escal':6A,82C 'exploit':16B,70C 'flaw':51C 'free':33B,64C 'gain':45B 'host':22B 'implement':58C 'incorrect':35B,63C 'infrastructur':17B 'instruct':90C 'kernel':2A,4A,15A,25B,48C 'kubernet':18B 'lead':61C 'linux':1A,3A,14A,19B,24B,47C 'local':37B,67C 'machin':42B 'memori':34B,65C 'packet':27B,30B,54C,57C 'per':88C 'possibl':44B,79C 'privileg':5A,81C 'requir':84C 'root':46B 'self':21B 'self-host':20B 'servic':76C 'socket':28B,55C 'updat':87C 'user':38B,68C 'vendor':89C 'vulner':7A","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2022-01-26T14:15:08+00:00","kev":{"dateAdded":"2022-04-11","dueDate":"2022-05-02","requiredAction":"Apply updates per vendor instructions.","knownRansomwareCampaignUse":"Unknown"},"cvss_vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:H","cvss_by":"cve-coordination@google.com","poc_count":0,"sources":[{"source":"kev","external_id":"CVE-2021-22600","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-22600","severity":null,"published_at":"2022-04-11T00:00:00+00:00","modified_at":null,"first_seen_at":"2026-10-23T19:11:52+00:00","fetched_at":"2026-10-25T17:39:57+00:00","note":null},{"source":"epss","external_id":"CVE-2021-22600","url":"https://api.first.org/data/v1/epss?cve=CVE-2021-22600","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-23T19:13:44+00:00","fetched_at":"2026-10-23T19:13:44+00:00","note":null},{"source":"nvd","external_id":"CVE-2021-22600","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-22600","severity":null,"published_at":"2022-01-26T14:15:08+00:00","modified_at":"2026-06-17T03:37:27+00:00","first_seen_at":"2026-10-23T21:57:35+00:00","fetched_at":"2026-10-23T21:57:35+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}