Python EUVD-2026-13433

Local attacker creates malicious DICOMDIR file with ReferencedFileID pointing outside File-set root. Victim must open/process it with pydicom 2.0.0-rc.1 through 3.0.1 using FileSet operations (copy, write, remove+write). Enables arbitrary file read/write/delete on victim's system.

The real-world risk is moderately elevated but requires specific conditions for exploitation. The CVSS vector (AV:L/AC:L/PR:N/UI:R) indicates local attack vector with low complexity but requiring user interaction, meaning an attacker must convince a user to open a malicious DICOMDIR file. The high impact ratings (C:H/I:H/A:H) reflect that successful exploitation can lead to arbitrary file access and manipulation. However, the requirement for local access and user interaction significantly constrains the attack surface compared to remotely exploitable vulnerabilities. No KEV listing or EPSS score was provided, suggesting no known active exploitation in the wild. The vulnerability affects medical imaging workflows where DICOM files are commonly exchanged, making social engineering via malicious medical image sets a plausible attack vector. Organizations processing DICOM files from untrusted sources face the highest risk, while those operating in controlled environments with trusted file sources have lower exposure.

An attacker crafts a malicious DICOMDIR file containing ReferencedFileID entries with path traversal sequences like '../../../../etc/passwd' or pointing to sensitive system files. When a healthcare professional or researcher opens this file using a vulnerable pydicom-based application (such as a medical imaging viewer or DICOM file management tool), the application processes the FileSet operations, inadvertently reading, copying, or deleting files outside the intended DICOM directory structure, potentially exposing patient data, credentials, or system configuration files.