Executive Summary
In December 2025, a significant vulnerability was disclosed in the Grassroots DICOM (GDCM) library, a critical open-source imaging component widely used in healthcare systems worldwide. Identified as CVE-2025-11266, this out-of-bounds write vulnerability could be triggered by simply opening a specially-crafted DICOM file, potentially crashing affected applications such as SimpleITK and medInria. The flaw, present in versions GDCM 3.0.24 and earlier, allows for denial-of-service and partial data and integrity impacts, increasing operational risk for healthcare environments that rely on medical imaging interoperability.
This incident highlights the persistent risk posed by vulnerable third-party libraries in regulated industries like healthcare. The rise in supply chain threats and software dependencies magnifies the urgency for organizations to maintain rigorous patching practices and robust segmentation, as attackers increasingly target widely-deployed open-source components to disrupt critical services.
Why This Matters Now
Healthcare organizations continue to rely on open-source imaging libraries like GDCM, which, if not promptly updated, expose patient care to disruption through denial-of-service attacks. The incident underscores the urgent need for proactive vulnerability management and defense-in-depth strategies amid ongoing supply chain security concerns.
Attack Path Analysis
An attacker delivers a maliciously crafted DICOM file to a targeted healthcare system endpoint with GDCM parsing enabled, exploiting a local file-handling vulnerability when a user opens the file. No additional privilege escalation is necessary, but if the attacker gains code execution, they may attempt to pivot to other hosts within the internal network. Movement within segmented workloads or containers could occur if east-west controls are weak. Command & Control may be established if outbound network policies are overly permissive, enabling callbacks or external reachback. Exfiltration is less relevant for this DoS class, but attacker-controlled channels could theoretically be leveraged for data egress. The primary impact is application crash and denial of service, disrupting healthcare operations reliant on imaging workflows.
Kill Chain Progression
Initial Compromise
Description
Attacker delivers a specially crafted DICOM file to a target endpoint (via phishing or media transfer), triggering an out-of-bounds write when the file is processed locally.
Related CVEs
CVE-2025-11266
CVSS 6.6An out-of-bounds write vulnerability in Grassroots DICOM (GDCM) allows attackers to cause a denial-of-service condition by opening a crafted DICOM file.
Affected Products:
Grassroots DICOM (GDCM) – <= 3.0.24
SimpleITK SimpleITK – <= 2.5.2
medInria medInria – <= 4.0
Exploit Status:
no public exploit
MITRE ATT&CK® Techniques
Phishing: Spearphishing Attachment
User Execution: Malicious File
Endpoint Denial of Service
Access Token Manipulation
Abuse Elevation Control Mechanism: Bypass User Access Control
Exploitation for Privilege Escalation
Exploitation for Client Execution
Potential Compliance Exposure
Mapping incident impact across multiple compliance frameworks.
PCI DSS 4.0 – Vulnerability Management Program
Control ID: 6.2.1
NIS2 Directive – Security in Network and Information Systems
Control ID: Art. 21(2)(d)
NYDFS 23 NYCRR 500 – Cybersecurity Policy
Control ID: 500.03
CISA ZTMM 2.0 – Continuous Application Vulnerability Management
Control ID: Application Workload Pillar - Application Vulnerability Management
DORA (Digital Operational Resilience Act) – ICT Risk Management and ICT Systems Security
Control ID: Art. 9(2)
Sector Implications
Industry-specific impact of the vulnerabilities, including operational, regulatory, and cloud security risks.
Health Care / Life Sciences
DICOM vulnerability in medical imaging systems creates denial-of-service risks, compromising patient care workflows and medical device availability in healthcare facilities.
Medical Equipment
Out-of-bounds write vulnerability affects medical imaging devices using GDCM library, requiring immediate patches to prevent application crashes and equipment failures.
Information Technology/IT
DICOM parsing vulnerability impacts IT infrastructure supporting medical imaging systems, requiring network segmentation and secure file handling protocols for mitigation.
Government Administration
CISA advisory highlights critical infrastructure vulnerability affecting government healthcare facilities and public health systems requiring coordinated defensive measures and patch management.
Sources
- Grassroots DICOM (GDCM)https://www.cisa.gov/news-events/ics-medical-advisories/icsma-25-345-01Verified
- CVE-2025-11266 Detailhttps://nvd.nist.gov/vuln/detail/CVE-2025-11266Verified
- GDCM Release v3.2.2https://github.com/malaterre/GDCM/releases/tag/v3.2.2Verified
Frequently Asked Questions
Cloud Native Security Fabric Mitigations and ControlsCNSF
Zero Trust segmentation, secure east-west traffic controls, and enforced egress filtering would have confined attacker movement, reduced lateral risk, and blocked outbound callbacks following local exploitation of the vulnerable DICOM parser.
Control: Cloud Native Security Fabric (CNSF)
Mitigation: Real-time policy enforcement restricts file access to approved applications.
Control: Kubernetes Security (AKF)
Mitigation: Pod and namespace segmentation confines privilege escalation risk.
Control: Zero Trust Segmentation
Mitigation: Lateral network movement is blocked between unauthorized segments.
Control: Egress Security & Policy Enforcement
Mitigation: Outbound C2 traffic to unauthorized domains/IPs is detected and blocked.
Control: Cloud Firewall (ACF)
Mitigation: Policy-based firewalling blocks unauthorized outbound data flows.
Abnormal crash or DoS activity is detected for rapid incident response.
Impact at a Glance
Affected Business Functions
- Medical Imaging
- Patient Diagnostics
Estimated downtime: 2 days
Estimated loss: $50,000
Potential exposure of patient imaging data due to application crashes.
Recommended Actions
Key Takeaways & Next Steps
- • Upgrade Grassroots DICOM (GDCM) and all dependent applications to patched versions immediately.
- • Implement Zero Trust Segmentation to isolate DICOM processing workloads from broader network access.
- • Enforce egress filtering and cloud firewalling to restrict external communications from sensitive healthcare workloads.
- • Apply runtime anomaly detection and incident response for rapid identification of application crashes or abnormal activity.
- • Regularly revisit cloud workload security configurations to ensure principle of least privilege and limit blast radius for future exploits.
