CVE-2021-27852
RCE in Checkbox Survey ≤ 7.0
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2021-27852 is a critical-severity Deserialization of Untrusted Data (CWE-502) vulnerability in Checkbox Survey. Its CVSS base score is 9.8 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Junk Data (T1001.001); ranked in the top 2% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2021-27852 is a deserialization of untrusted data vulnerability (CWE-502) located in CheckboxWeb.dll within Checkbox Survey. The flaw affects all versions prior to 7 and carries a CVSS 3.1 base score of 9.8, reflecting network-accessible attack complexity that is both low and unauthenticated.
An unauthenticated remote attacker can supply a crafted serialized object to CheckboxWeb.dll, triggering arbitrary code execution on the server with no user interaction required. Successful exploitation grants the attacker full confidentiality, integrity, and availability impact on the affected survey application.
The vulnerability is tracked in the CISA Known Exploited Vulnerabilities catalog and referenced in CERT/CC advisory VU#706695, indicating that official sources treat it as actively exploited and recommend applying the vendor-supplied update to version 7 or later as the primary mitigation.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2021-14590
Vulnerability Data
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(s)
- KEV Date Added
- 11 April 2022
Related Threats
Threat-Actor AttributionAI
MITRE ATT&CK Enterprise Techniques
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Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Penetration testing supplies malicious serialized objects, detecting unsafe deserialization and supporting corrective actions.
Evaluation of untrusted data handling (deserialization testing) reveals unsafe processing, which the required remediation process addresses.
Untrusted serialized data can be deserialized and observed inside the chamber, blocking gadget-chain exploitation outside the sandbox.
Validates or rejects untrusted serialized data before deserialization occurs.
Identifies and blocks malicious code introduced through deserialization of untrusted data at system boundaries.
Integrity verification of serialized information can detect tampering before deserialization occurs.
Provenance of associated data allows detection of untrusted sources before deserialization or processing occurs.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
PR.PS-02 addresses only post-deployment updates/patching and cannot prevent introduction of unsafe deserialization code, yet it can remediate some instances when the flaw exists in outdated libraries or components.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.