CVE-2026-5437 Overview
An out-of-bounds read vulnerability exists in DicomStreamReader during DICOM meta-header parsing. When processing malformed metadata structures, the parser may read beyond the bounds of the allocated metadata buffer. Although this issue does not typically crash the server or expose data directly to the attacker, it reflects insufficient input validation in the parsing logic.
Critical Impact
This vulnerability allows attackers to trigger out-of-bounds memory reads by sending specially crafted DICOM files with malformed metadata, potentially leading to information disclosure or denial of service in medical imaging systems.
Affected Products
- DICOM Server implementations using vulnerable DicomStreamReader components
- Medical imaging software with DICOM parsing capabilities
- Orthanc Server and related DICOM processing applications
Discovery Timeline
- April 9, 2026 - CVE CVE-2026-5437 published to NVD
- April 9, 2026 - Last updated in NVD database
Technical Details for CVE-2026-5437
Vulnerability Analysis
This out-of-bounds read vulnerability occurs within the DicomStreamReader component responsible for parsing DICOM meta-headers. DICOM (Digital Imaging and Communications in Medicine) is a standard format used extensively in medical imaging systems for storing and transmitting patient scan data. The vulnerability stems from improper bounds checking when the parser processes metadata structures within DICOM files.
When a malformed DICOM file with an invalid or specially crafted metadata structure is processed, the parser fails to properly validate the boundaries of the metadata buffer before attempting to read from it. This can result in the parser reading memory locations beyond the allocated buffer, potentially accessing adjacent memory regions.
While this vulnerability does not typically result in a server crash or direct data exposure to remote attackers, it represents a significant security concern in medical imaging environments where data integrity and system reliability are paramount.
Root Cause
The root cause of this vulnerability is insufficient input validation in the DICOM meta-header parsing logic within the DicomStreamReader component. Specifically, the parser does not adequately verify that the size fields within the metadata structure are consistent with the actual allocated buffer size before performing read operations. This allows specially crafted DICOM files with inconsistent or manipulated size values to trigger out-of-bounds memory access.
Attack Vector
An attacker can exploit this vulnerability by crafting a malicious DICOM file containing malformed metadata structures with manipulated size fields or boundary values. When this file is processed by a vulnerable DICOM server or application, the DicomStreamReader parser attempts to read beyond the allocated metadata buffer.
The attack can be delivered through various vectors depending on the deployment scenario:
- Direct upload of malformed DICOM files to a DICOM server
- Network transmission of malicious DICOM data via DICOM network protocols
- Processing of DICOM files received from external medical imaging devices
The malformed metadata structure typically contains size indicators that exceed the actual buffer allocation, causing the parser to read memory beyond the intended boundaries. For detailed technical information, refer to the CERT Vulnerability Report #536588.
Detection Methods for CVE-2026-5437
Indicators of Compromise
- Unusual memory access patterns or segmentation faults in DICOM processing services
- Abnormal system behavior when processing DICOM files from untrusted sources
- Log entries indicating parsing errors or buffer-related exceptions in DicomStreamReader
Detection Strategies
- Monitor DICOM server logs for repeated parsing failures or exceptions related to metadata processing
- Implement network traffic analysis to detect malformed DICOM file transmissions
- Deploy memory monitoring tools to identify out-of-bounds read attempts in DICOM processing applications
- Use application-level firewalls capable of inspecting DICOM protocol traffic for malformed structures
Monitoring Recommendations
- Enable verbose logging on DICOM servers to capture detailed parsing events and errors
- Implement alerting for unusual patterns of DICOM file processing failures
- Monitor system memory usage and access patterns during DICOM file processing operations
- Review DICOM server access logs for suspicious file upload patterns
How to Mitigate CVE-2026-5437
Immediate Actions Required
- Review DICOM server configurations and restrict file uploads to trusted sources only
- Implement input validation at the network perimeter for DICOM file transfers
- Consider temporarily isolating DICOM processing systems from untrusted networks until patches are applied
- Monitor systems for signs of exploitation attempts
Patch Information
Administrators should consult the following resources for patch availability and remediation guidance:
- CERT Vulnerability Report #536588 - Security advisory with vulnerability details
- Orthanc Server Overview - For Orthanc-specific updates and patches
- Machine Spirits Home Page - Vendor information and updates
Contact your DICOM software vendor for specific patch information and apply security updates as soon as they become available.
Workarounds
- Restrict DICOM file processing to files from trusted and verified sources only
- Implement strict network segmentation to isolate DICOM servers from untrusted network segments
- Deploy additional input validation layers before files reach the vulnerable parsing component
- Consider using DICOM file sanitization tools to preprocess files before server ingestion
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
