{"id":"CVE-2021-42237","kind":"vulnerability","aliases":["CVE-2021-42237"],"related":[],"title":"Sitecore XP: Sitecore XP Remote Command Execution Vulnerability","description":"Sitecore XP 7.5 Initial Release to Sitecore XP 8.2 Update-7 is vulnerable to an insecure deserialization attack where it is possible to achieve remote command execution on the machine. No authentication or special configuration is required to exploit this vulnerability.","summary":"Sitecore XP contains an insecure deserialization flaw that lets an attacker send crafted requests to run code on the server. It is on CISA's known-exploited list and EPSS rates it 0.976, and the sources tag it with ransomware use.","severity":"critical","cvss":10.0,"epss":0.97566,"exploited":true,"exploited_at":"2022-03-25T00:00:00+00:00","products":[{"name":"Sitecore XP","fixed":[],"affected":"","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["exploited","ransomware","self-hosted","sitecore-xp","vendor","windows"],"not_affected_if":["managed-hosting"],"how_to_check":null,"fix":"Apply the update per Sitecore's vendor instructions; the sources do not name the fixed version.","status":"open","published_at":"2021-11-05T10:15:08+00:00","first_seen_at":"2026-10-23T19:11:52+00:00","triaged_at":"2026-10-23T21:20:01+00:00","updated_at":"2026-10-23T21:57:35+00:00","category":"vendor","confidence":0.6,"triage":{"at":"2026-10-23T21:20:01Z","model":"claude-haiku-5-5","output":{"fix":"Apply the update per Sitecore's vendor instructions; the sources do not name the fixed version.\nunknown","reach":"internet","impact":"high","summary":"Sitecore XP contains an insecure deserialization flaw that lets an attacker send crafted requests to run code on the server. It is on CISA's known-exploited list and EPSS rates it 0.976, and the sources tag it with ransomware use.","category":"vendor","who_cares":["sitecore-xp","self-hosted","windows"],"confidence":0.6,"needs_auth":"unknown","worst_case":"Attacker runs arbitrary code on the Sitecore server remotely.","analyst_note":"Find the affected and fixed Sitecore XP versions and the exposure check from Sitecore's advisory and the CISA KEV entry, since the sources give no version or check.","how_to_check":"unknown","needs_analyst":true,"not_affected_if":["managed-hosting"],"user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"critical"},"cost_usd":0.000462,"input_tokens":2813,"output_tokens":362,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2021':10A,13A '-42237':11A,14A '-7':79C '0.976':60B '7.5':71C '8.2':77C 'achiev':92C 'attack':37B,86C 'authent':100C 'cisa':50B 'code':43B 'command':6A,94C 'configur':103C 'contain':29B 'craft':39B 'cve':9A,12A 'deseri':32B,85C 'epss':57B 'execut':7A,95C 'exploit':17B,54B,107C 'flaw':33B 'host':21B 'initi':72C 'insecur':31B,84C 'known':53B 'known-exploit':52B 'let':35B 'list':55B 'machin':98C 'possibl':90C 'ransomwar':18B,67B 'rate':58B 'releas':73C 'remot':5A,93C 'request':40B 'requir':105C 'run':42B 'self':20B 'self-host':19B 'send':38B 'server':46B 'sitecor':1A,3A,23B,27B,69C,75C 'sitecore':15A 'sitecore-xp':22B 'sourc':63B 'special':102C 'tag':64B 'updat':78C 'use':68B 'vendor':25B 'vulner':8A,81C,109C 'window':26B 'xp':2A,4A,16A,24B,28B,70C,76C","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2021-11-05T10:15:08+00:00","kev":{"dateAdded":"2022-03-25","dueDate":"2022-04-15","requiredAction":"Apply updates per vendor instructions.","knownRansomwareCampaignUse":"Known"},"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cvss_by":"nvd@nist.gov","poc_count":0,"sources":[{"source":"kev","external_id":"CVE-2021-42237","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-42237","severity":null,"published_at":"2022-03-25T00:00:00+00:00","modified_at":null,"first_seen_at":"2026-10-23T19:11:52+00:00","fetched_at":"2026-10-25T16:39:48+00:00","note":null},{"source":"epss","external_id":"CVE-2021-42237","url":"https://api.first.org/data/v1/epss?cve=CVE-2021-42237","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-2021-42237","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-42237","severity":null,"published_at":"2021-11-05T10:15:08+00:00","modified_at":"2026-07-09T13:57:14+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"}