Is CVE-2021-27852 in the CISA KEV catalog?

Yes. CVE-2021-27852 is on the CISA Known Exploited Vulnerabilities list, added 2022-04-11.

What is the CVSS severity of CVE-2021-27852?

CVE-2021-27852 has a CVSS v3 base score of 9.8 (CRITICAL).

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

CVE-2021-27852 has an EPSS score of 31.95% (98th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2021-27852

CRITICALCISA KEVEPSS 98th pctl

9.8

CVSS v3

NVD

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.

CWE-502Deserialization of Untrusted Data

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploit Intelligence

31.95%probability of exploitation in 30 days

98thpercentile

Very high risk: more likely to be exploited than 98% of all known CVEs.

Known Exploited Vulnerability (CISA KEV)

Checkbox Survey Deserialization of Untrusted Data Vulnerability

Deserialization of Untrusted Data vulnerability in CheckboxWeb.dll of Checkbox Survey allows an unauthenticated remote attacker to execute arbitrary code.

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.

Remediation due: 2022-05-02

References

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-10-24.