CVE-2021-4478: Dräger CC-Vision Buffer Overflow Flaw

CVE-2021-4478 Overview

CVE-2021-4478 is an out-of-bounds write vulnerability [CWE-787] affecting Dräger CC-Vision Basic before version 7.5.3 and Dräger CC-Vision E-Cal before version 7.2.5.0. The flaw occurs when the application parses a crafted .gdt file, triggering a buffer overflow during file parsing. An attacker who convinces a user to open a malicious .gdt file can crash the application or execute arbitrary code in the context of the user.

Critical Impact

A crafted .gdt file can trigger memory corruption that enables local code execution on systems running affected Dräger CC-Vision software.

Affected Products

• Dräger CC-Vision Basic versions prior to 7.5.3
• Dräger CC-Vision E-Cal versions prior to 7.2.5.0
• Workstations parsing .gdt files with affected CC-Vision installations

Discovery Timeline

• 2026-06-02 - CVE-2021-4478 published to the National Vulnerability Database
• 2026-06-03 - Last updated in NVD database

Technical Details for CVE-2021-4478

Vulnerability Analysis

The vulnerability resides in the .gdt file parser used by Dräger CC-Vision Basic and CC-Vision E-Cal. The Geräte-Daten-Träger (GDT) format is a text-based exchange format used for transferring patient and measurement data. When parsing a malformed .gdt file, the application writes past the end of an allocated buffer, corrupting adjacent memory. This memory corruption can cause an application crash or, with carefully constructed input, divert execution flow to attacker-controlled code.

Root Cause

The root cause is insufficient bounds checking during .gdt file parsing, categorized as an out-of-bounds write [CWE-787]. The parser fails to validate field lengths or record sizes contained within the .gdt structure before copying data into a fixed-size buffer. Attacker-supplied length values or oversized fields cause the parser to overflow the destination buffer.

Attack Vector

Exploitation requires local file access and user interaction. An attacker delivers a crafted .gdt file through email, removable media, or a shared network location. When a user opens the file in CC-Vision Basic or CC-Vision E-Cal, the parser processes the malicious content and triggers the overflow. Successful exploitation grants code execution under the privileges of the logged-in user.

No verified proof-of-concept code is publicly available. Technical details are documented in the Draeger Product Security Advisory and the VulnCheck Out-of-Bounds Write Advisory.

Detection Methods for CVE-2021-4478

Indicators of Compromise

• Unexpected crashes of CC-Vision Basic.exe or CC-Vision E-Cal.exe processes following the opening of a .gdt file
• Presence of .gdt files from untrusted sources in user directories, mail attachments, or removable media
• Windows Error Reporting entries referencing access violations in CC-Vision binaries
• Spawning of unexpected child processes by CC-Vision executables

Detection Strategies

• Monitor for child process creation events originating from CC-Vision executables, which should not normally spawn interactive shells or scripting engines
• Track file open events targeting .gdt files combined with subsequent process crash telemetry
• Inspect .gdt files for malformed record headers or oversized field lengths inconsistent with the GDT specification

Monitoring Recommendations

• Enable Windows Defender Exploit Guard or equivalent memory integrity controls on hosts running CC-Vision
• Forward application crash events (Event ID 1000) and process creation events (Event ID 4688) to a centralized log platform
• Alert on CC-Vision processes loading non-standard DLLs or making outbound network connections after parsing a .gdt file

How to Mitigate CVE-2021-4478

Immediate Actions Required

• Upgrade Dräger CC-Vision Basic to version 7.5.3 or later
• Upgrade Dräger CC-Vision E-Cal to version 7.2.5.0 or later
• Inventory all systems running CC-Vision software and prioritize patching for hosts that process .gdt files from external sources
• Restrict the ability to open .gdt files to authenticated, trusted users only

Patch Information

Dräger has released fixed versions addressing the out-of-bounds write. Customers should obtain the updated installers from Dräger and apply them according to the vendor advisory. Refer to the Draeger Product Security Advisory for version-specific guidance and download instructions.

Workarounds

• Do not open .gdt files received from untrusted or unverified sources
• Block .gdt file attachments at the email gateway when not required for business operations
• Run CC-Vision under a standard user account rather than a privileged account to limit the impact of successful exploitation
• Use application allowlisting to prevent CC-Vision processes from spawning shells, scripting hosts, or other unexpected child processes

# Verify installed CC-Vision Basic version on Windows hosts
reg query "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall" /s /f "CC-Vision"