What’s Vulnerable › Vulnerabilities

CVE-2026-5442: Heap Buffer Overflow in DICOM Image Decoder via VR UL Dimensions

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-04-09 · updated 2026-10-26
• Weakness: CWE-787

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.

Affected products

• orthanc-server orthanc: before 1.12.11 — fixed in 1.12.11

How to fix

Upgrade to a fixed version: orthanc-server orthanc 1.12.11. Check the vendor advisory for mitigations.

References

• https://kb.cert.org/vuls/id/536588
• https://www.machinespirits.de/
• https://www.orthanc-server.com/

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