CVE-2025-3483: MedDream PACS Server RCE Vulnerability

CVE-2025-3483 Overview

CVE-2025-3483 is a stack-based buffer overflow vulnerability in MedDream PACS Server that allows arbitrary code execution through malicious DICOM file parsing. The flaw exists in the routine responsible for processing Digital Imaging and Communications in Medicine (DICOM) files, where user-supplied data is copied into a fixed-length stack buffer without proper length validation [CWE-121]. An attacker who convinces a user to open or process a crafted DICOM file can execute code in the context of the service account. The vulnerability was reported through the Zero Day Initiative as ZDI-CAN-25825 and disclosed publicly as ZDI-25-243.

Critical Impact

Successful exploitation provides arbitrary code execution under the PACS service account, enabling full compromise of medical imaging infrastructure that stores and routes patient data.

Affected Products

• MedDream PACS Server (Premium edition)
• Installations parsing untrusted DICOM files
• Healthcare environments exposing PACS endpoints to imaging input

Discovery Timeline

• 2025-05-22 - CVE-2025-3483 published to NVD
• 2025-07-11 - Last updated in NVD database

Technical Details for CVE-2025-3483

Vulnerability Analysis

The vulnerability resides in MedDream PACS Server's DICOM file parser. DICOM is the standard format for storing and transmitting medical imaging data, and PACS (Picture Archiving and Communication System) servers routinely ingest these files from imaging modalities and external sources. The parser copies attacker-controlled fields from the DICOM structure into a fixed-size buffer allocated on the stack without verifying that the source length fits the destination.

When the supplied data exceeds the buffer size, adjacent stack memory is overwritten. This includes saved return addresses, frame pointers, and structured exception handler records on Windows. An attacker controlling the overflowed bytes can hijack control flow and pivot to a payload of their choice.

Root Cause

The root cause is the absence of bounds checking before a memory copy operation on a stack buffer, classified under [CWE-121] Stack-based Buffer Overflow. The parser trusts length or content fields embedded within the DICOM file rather than constraining writes to the destination buffer capacity. Standard mitigations such as safe string functions or explicit length checks are not applied in the affected code path.

Attack Vector

Exploitation requires user interaction. An attacker delivers a malicious DICOM file to the target environment through email, a shared imaging workflow, a compromised modality, or upload to a PACS ingestion endpoint. When the file is parsed, the overflow triggers and code executes in the context of the MedDream service account. Because authentication is not required to exploit the parsing flaw itself, any file that reaches the parser can be weaponized.

The MedDream service account typically holds privileges sufficient to access stored medical images, configuration, and database connections, making the impact on confidentiality, integrity, and availability uniformly high.

No public proof-of-concept exploit is available at the time of writing. Refer to the Zero Day Initiative Advisory ZDI-25-243 for vendor coordination details.

Detection Methods for CVE-2025-3483

Indicators of Compromise

• Unexpected child processes spawned by the MedDream PACS Server service, particularly command interpreters or scripting engines
• Crashes or restarts of the PACS parsing process correlated with newly ingested DICOM files
• DICOM files with anomalously large tag values or malformed structure entering the ingestion pipeline
• Outbound network connections from the PACS host to unrecognized destinations following file processing

Detection Strategies

• Monitor process creation telemetry for the MedDream service account spawning non-standard binaries
• Apply file content inspection to incoming DICOM files for oversized fields and structural anomalies
• Alert on stack overflow exception events and Windows Error Reporting entries tied to the PACS process
• Correlate file ingestion timestamps with crash or anomalous behavior in security analytics

Monitoring Recommendations

• Enable verbose logging on the PACS service and forward logs to a centralized SIEM for retention and correlation
• Track inbound DICOM submissions, including source IP, modality identifier, and file hash
• Baseline normal PACS service behavior to surface deviations such as new outbound connections or memory access violations
• Audit service account activity for privilege use that falls outside imaging workflows

How to Mitigate CVE-2025-3483

Immediate Actions Required

• Restrict network access to the MedDream PACS Server so only trusted imaging modalities and authorized clients can submit DICOM files
• Run the PACS service under a least-privilege account that cannot access systems beyond its operational scope
• Validate and sandbox DICOM files at the ingestion boundary before they reach the parser
• Review the ZDI advisory ZDI-25-243 and contact MedDream for current patch availability

Patch Information

MedDream coordinated this disclosure with the Zero Day Initiative under tracker ZDI-CAN-25825. Administrators should consult MedDream support channels and the Zero Day Initiative Advisory ZDI-25-243 for the fixed version and apply the vendor-supplied update across all affected PACS instances.

Workarounds

• Block DICOM ingestion from untrusted sources at the network perimeter until patching is complete
• Disable automatic processing of DICOM attachments received through email or web upload
• Apply application allowlisting to prevent the PACS service account from launching unexpected executables
• Segment PACS infrastructure from general-purpose networks to limit lateral movement after compromise

# Example: restrict inbound DICOM port (default 11112) to trusted modalities
# Windows Firewall rule
netsh advfirewall firewall add rule name="PACS-DICOM-Allow-Modalities" \
  dir=in action=allow protocol=TCP localport=11112 \
  remoteip=10.0.10.0/24

netsh advfirewall firewall add rule name="PACS-DICOM-Block-All" \
  dir=in action=block protocol=TCP localport=11112