How severe is CVE-2021-27852?

CVE-2021-27852 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-27852 being actively exploited?

Yes. CVE-2021-27852 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2022-04-11, which means active exploitation has been confirmed. It should be prioritised for remediation.

What products are affected by CVE-2021-27852?

CVE-2021-27852 affects Checkbox Survey. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-27852?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.

Does CVE-2021-27852 have an EU (EUVD) identifier?

Yes. CVE-2021-27852 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-14590. It is also flagged as exploited in the EUVD (since 2022-04-11).

When was CVE-2021-27852 published?

CVE-2021-27852 was published on 2021-05-27 and last updated on 2026-06-17.

CVE-2021-27852

CVE-2021-27852 is a critical-severity vulnerability in Checkbox Survey with a CVSS 3.x base score of 9.8. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2022-04-11). The underlying weakness is classified as CWE-502.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 32% (98th percentile)
Actively exploited: Yes — listed in CISA KEV (added 2022-04-11)
EU (EUVD) id: EUVD-2021-14590
EU exploitation: Flagged exploited in the ENISA EU Vulnerability Database (since 2022-04-11)
Weakness: CWE-502
Affected product: Checkbox Survey
Published: 2021-05-27
Last modified: 2026-06-17

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.

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.
How severe is CVE-2021-27852?: CVE-2021-27852 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-27852 being actively exploited?: Yes. CVE-2021-27852 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2022-04-11, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2021-27852?: CVE-2021-27852 affects Checkbox Survey. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-27852?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2021-27852 have an EU (EUVD) identifier?: Yes. CVE-2021-27852 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-14590. It is also flagged as exploited in the EUVD (since 2022-04-11).
When was CVE-2021-27852 published?: CVE-2021-27852 was published on 2021-05-27 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:checkbox:survey:*:*:*:*:*:*:*:*

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