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ExploitedIn CISA KEVFix available

CVE-2021-27852

Exploitation confirmed. First attested on 2022-04-11 by CISA-ADP, CISA KEV, GCVE · kevintel.

  • Published2021-05-27
  • Fixed in7.0
  • WeaknessCWE-502

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2021-05-2721:15CVE publishedNVD
  2. 2022-04-11Added to the CISA KEV catalogCISA KEV
  3. 2022-04-11Listed as exploited by GCVEGCVE
  4. 2022-04-11Exploitation first reportedCISA KEV
  5. 2025-02-0619:47SSVC exploitation set to activeCISA-ADP

Observed activity

isMalicious corpus · updated 2026-11-03 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-27852?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-27852?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Checkbox survey
BranchAffectedFixed in
7.0< 7.07.0

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA1 product

As certcc, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • Checkbox Survey
    Affected
    • < 7fixed in 7custom

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2023-10-13

Fix

  1. Update Checkbox survey to 7.0
  2. CISA’s required action: 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.due 2022-05-02

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub
Metasploit modules
none listed
Metasploit Framework

CISA Known Exploited Vulnerability

Date Added
2022-04-11
Patch Due Date
2022-05-02
Ransomware Use
Unknown
Required Action
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.

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
2021-05-27
Last Modified
2026-06-17
NVD status
Analyzed
GitHub Advisory
GHSA-xrx4-vq84-23w6

Frequently asked questions

What is CVE-2021-27852?

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.

Is CVE-2021-27852 actively exploited?

Yes. CVE-2021-27852 is on the CISA Known Exploited Vulnerabilities (KEV) catalog, meaning it has been confirmed as actively exploited in the wild. CISA requires federal agencies to patch by 2022-05-02.

What is the CVSS score for CVE-2021-27852?

CVE-2021-27852 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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Sources for this record