Heap Buffer Overflow in DICOM Decoder Causes Memory Corruption

Publication date: 2026-04-09

Last updated on: 2026-04-14

Assigner: CERT/CC

Description

A heap buffer overflow vulnerability exists in the DICOM image decoder. Dimension fields are encoded using Value Representation (VR) Unsigned Long (UL), instead of the expected VR Unsigned Short (US), which allows extremely large dimensions to be processed. This causes an integer overflow during frame size calculation and results in out-of-bounds memory access during image decoding.

CVSS Scores

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Meta Information

Published

2026-04-09

Last Modified

2026-04-14

Generated

2026-07-06

AI Q&A

2026-04-09

EPSS Evaluated

2026-07-05

NVD

CVE-2026-5442

EUVD

EUVD-2026-20920

Affected Vendors & Products

Vendor	Product	Version / Range
orthanc-server	orthanc	to 1.12.11 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-787	The product writes data past the end, or before the beginning, of the intended buffer.

Attack-Flow Graph

Executive Summary

This vulnerability is a heap buffer overflow in the DICOM image decoder. It occurs because the dimension fields are encoded using the Value Representation (VR) Unsigned Long (UL) instead of the expected VR Unsigned Short (US). This mismatch allows extremely large dimension values to be processed, which causes an integer overflow during the calculation of the frame size. As a result, the decoder accesses memory out-of-bounds while decoding the image.

Impact Analysis

The heap buffer overflow caused by this vulnerability can lead to out-of-bounds memory access during image decoding. This can result in application crashes, data corruption, or potentially allow an attacker to execute arbitrary code, compromising the security and stability of the affected system.

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