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Vulnerability record · CVE-2026-5442 · published 9 April 2026

CVE-2026-5442: Orthanc-server orthanc out-of-bounds write vulnerability

Orthanc Server · Orthanc

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.

9.8 CVSS 3.1 Critical EPSS 0.92% · top 41.3% CWE-787 · Out-of-bounds write
9.8CVSS 3.1 base score
0.92%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
3References
17 Jun 2026Last modified by NVD

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

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://kb.cert.org/vuls/id/536588 Third Party AdvisoryVDB Entry
https://www.machinespirits.de/ Not Applicable
https://www.orthanc-server.com/ Product

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-5442), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.