{"id":"CVE-2021-27852","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-27852","generatedAt":"2026-10-27T22:33:54.954Z","title":"Checkbox Survey Deserialization of Untrusted Data Vulnerability","description":"Deserialization of Untrusted Data vulnerability in CheckboxWeb.dll of Checkbox Survey allows an unauthenticated remote attacker to execute arbitrary code. This issue affects: Checkbox Survey versions prior to 7.","published":"2021-05-27T21:15:21.000Z","lastModified":"2026-06-17T03:45:31.000Z","status":"Analyzed","sourceIdentifier":"cret@cert.org","cvss":{"version":"3.1","score":9.8,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"cwe":["CWE-502"],"affected":["checkbox/survey"],"epss":{"score":0.30258,"percentile":0.9821,"date":"2026-10-26","history":[{"date":"2026-09-24","score":0.30258,"percentile":0.98163}]},"kev":{"listed":true,"dateAdded":"2022-04-11","dueDate":"2022-05-02","knownRansomwareCampaignUse":"Unknown","notes":"Versions 6 and earlier for this product are end-of-life and must be removed from agency networks. Versions 7 and later are not considered vulnerable.\nhttps://nvd.nist.gov/vuln/detail/CVE-2021-27852"},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"urgent","text":"Known to be exploited in the wild (CISA KEV, CISA remediation deadline 2 May 2022). Treat as an emergency change: patch or isolate now, then hunt for prior compromise."},"changes":[],"references":[{"url":"https://www.kb.cert.org/vuls/id/706695","tags":["Third Party Advisory","US Government Resource"],"source":"cret@cert.org"},{"url":"https://www.kb.cert.org/vuls/id/706695","tags":["Third Party Advisory","US Government Resource"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-27852","tags":["US Government Resource"],"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-27852","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}