Cyber Resilience

CVE-2021-47831

MediumPublic PoC

Published: 16 January 2026

Published
16 January 2026
Modified
15 April 2026
KEV Added
Patch
CVSS Score v4 4.6 CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0003 9.3th percentile
Risk Priority 9 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-47831 is a medium-severity Improper Validation of Specified Quantity in Input (CWE-1284) vulnerability in Sandboxie Plus (inferred from references). Its CVSS base score is 4.6 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked at the 9.3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified are NIST 800-53 SC-5 (Denial-of-service Protection) and SI-10 (Information Input Validation).

Deeper analysis

CVE-2021-47831 is a denial of service vulnerability in Sandboxie version 5.49.7. The flaw occurs when attackers overflow the container folder input field, such as by pasting a large buffer of repeated characters into the Sandbox container folder setting, causing the application to crash.

The vulnerability has a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H), indicating it is exploitable over the network with low complexity, no privileges or user interaction required, and results in high impact to availability with no effects on confidentiality or integrity. Unauthenticated remote attackers can trigger the crash, denying service to Sandboxie users.

Advisories and references are available from sources including the Sandboxie-Plus website (https://sandboxie-plus.com/), Vulncheck (https://www.vulncheck.com/advisories/sandboxie-denial-of-service), and Exploit-DB (https://www.exploit-db.com/exploits/49844), which documents a proof-of-concept exploit. No specific patch or mitigation details are detailed in the provided information.

EU & UK References

Vulnerability details

Sandboxie 5.49.7 contains a denial of service vulnerability that allows attackers to crash the application by overflowing the container folder input field. Attackers can paste a large buffer of repeated characters into the Sandbox container folder setting to trigger an…

more

application crash.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1499.004 Application or System Exploitation Impact
Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.
Why these techniques?

Buffer overflow input crash directly enables application DoS via exploitation (T1499.004).

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

CVEs Like This One

CVE-2021-47827Shared CWE-1284
CVE-2021-47818Shared CWE-1284
CVE-2026-25863Shared CWE-1284
CVE-2026-8813Shared CWE-1284
CVE-2021-47824Shared CWE-1284
CVE-2025-12664Shared CWE-1284
CVE-2025-65548Shared CWE-1284
CVE-2025-14511Shared CWE-1284
CVE-2021-47821Shared CWE-1284
CVE-2026-2597Shared CWE-1284

Affected Assets

Sandboxie Plus
inferred from references and description; NVD did not file a CPE for this CVE

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

prevent

SI-10 requires validation of information inputs, directly preventing buffer overflows in the Sandboxie container folder input field by enforcing bounds and content checks.

prevent

SI-11 mandates graceful error handling for unexpected inputs, preventing application crashes from overflowing the container folder field.

preventdetect

SC-5 provides denial-of-service protection mechanisms tailored to limit the impact of remote exploits causing high availability disruptions like the Sandboxie crash.

References