Cyber Resilience

CVE-2021-47881

MediumPublic PoC

Published: 23 January 2026

Published
23 January 2026
Modified
15 April 2026
KEV Added
Patch
CVSS Score v4 6.7 CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/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 0.0015 4.4th percentile
Risk Priority 35 floored blend · peak EPSS

Summary

CVE-2021-47881 is a medium-severity Stack-based Buffer Overflow (CWE-121) vulnerability in Ddc Web (inferred from references). Its CVSS base score is 6.7 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Malicious File (T1204.002); ranked at the 4.4th 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 SI-10 (Information Input Validation) and SI-16 (Memory Protection).

Deeper analysis

CVE-2021-47881 is a local buffer overflow vulnerability (CWE-121) in dataSIMS Avionics ARINC 664-1 version 4.5.3, affecting Windows systems. The flaw occurs when the software processes the milstd1553result.txt file, enabling attackers to overwrite memory through a crafted file containing manipulated payload and alignment sections. It has a CVSS v3.1 base score of 8.4 (AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), indicating high severity due to complete confidentiality, integrity, and availability impacts with low attack complexity.

A local attacker requires only local access to the system with no privileges (PR:N) and no user interaction (UI:N). By placing a specially crafted milstd1553result.txt file in the expected location, the attacker can trigger the buffer overflow, potentially achieving arbitrary code execution on the affected Windows system through precise control of the payload and memory alignment.

Advisories and additional details are available from vendor sites at https://www.ddc-web.com/ and https://www.ddc-web.com/en/connectivity/databus/milstd1553-1/software-1/bu-69414?partNumber=BU-69414, a VulnCheck advisory at https://www.vulncheck.com/advisories/datasims-avionics-arinc-local-buffer-overflow, and a proof-of-concept exploit at https://www.exploit-db.com/exploits/49577. No specific patch or mitigation details are detailed in the primary description.

A proof-of-concept exploit published on Exploit-DB demonstrates practical exploitability, highlighting risks in avionics simulation environments where the software is deployed. The vulnerability was published on 2026-01-23.

EU & UK References

Vulnerability details

dataSIMS Avionics ARINC 664-1 version 4.5.3 contains a local buffer overflow vulnerability that allows attackers to overwrite memory by manipulating the milstd1553result.txt file. Attackers can craft a malicious file with carefully constructed payload and alignment sections to potentially execute arbitrary…

more

code on the Windows system.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1204.002 Malicious File Execution
An adversary may rely upon a user opening a malicious file in order to gain execution.
Why these techniques?

Local buffer overflow triggered by crafted file (milstd1553result.txt) directly enables arbitrary code execution via malicious file placement with no user interaction required.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2026-22923Shared CWE-121
CVE-2020-37066Shared CWE-121
CVE-2026-0660Shared CWE-121
CVE-2026-42468Shared CWE-121
CVE-2026-27267Shared CWE-121
CVE-2025-54483Shared CWE-121
CVE-2026-34690Shared CWE-121
CVE-2026-5654Shared CWE-121
CVE-2025-24075Shared CWE-121
CVE-2025-21128Shared CWE-121

Affected Assets

Ddc Web
inferred from references and description; NVD did not file a CPE for this CVE

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

prevent

Validating the content and bounds of the milstd1553result.txt file directly prevents the buffer overflow from crafted payloads and alignment sections.

prevent

Memory protection safeguards such as DEP and ASLR prevent arbitrary code execution resulting from the memory overwrite in dataSIMS Avionics ARINC 664-1.

prevent

Remediating the identified buffer overflow flaw in version 4.5.3 eliminates the vulnerability exploited via the milstd1553result.txt file.

References