9.3 Critical

MONAILabel Server Crash and Silent Inference Corruption via Crafted DICOM (pydicom DS/IS Validation Bypass)

CVE-2026-48705

Summary An unauthenticated remote attacker can crash a running MONAILabel server or silently corrupt its medical AI inference results by uploading a single crafted DICOM file (~132 KB) via the REST API. The vulnerability stems from pydicom's lack of validation for Decimal String (DS) and Integer String (IS) DICOM Value Representations, which allows NaN and infinity values to pass through MONAI's PydicomReader and propagate through the entire spatial transform and ML inference pipeline. No authentication is required for the default MONAILabel REST API. The attacker needs only network access to the server (default port 8000). Severity: CVSS 3.1: 8.7 HIGH CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:L CWE: CWE-20 (Improper Input Validation) → CWE-682 (Incorrect Calculation) Details Root Cause — Layer 1: pydicom accepts invalid VR values pydicom's DSfloat.new() calls Python's float(val), which silently accepts "NaN", "inf", and "-inf". The DICOM standard (PS3.5 Table 6.2-1) defines DS as digits 0-9, +, -, ., e only. NaN and inf are not valid DS values. The isvalidds() check only runs in RAISE validation mode, which is NOT the default. The default mode is WARN, which still…

Part of the AI stack

This affects MONAI, in Runtimes & formats.

Assessment

CVSS: 9.3 (v3.1)
Severity: Critical
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 27 October 2026
Last updated: 27 October 2026
Affected: pip · monai
Weakness: CWE-20

CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:L

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