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Orthanc DICOM Server

Memory Exhaustion via Forged ZIP Metadata

The ZIP archive processing routine allocates memory based on the uncompressed size stored in ZIP metadata without validating its value.

This advisory contains limited information during coordinated disclosure. Please check back later for full details.

Authored byVolker Schönefeld, Simon Weber2026-04-02
SeverityMediumCVSS 6.5CVSS 3.1 VectorAV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HCWECWE-400 (Uncontrolled Resource Consumption)ProductOrthanc DICOM ServerAffected VersionsOrthanc <= 1.12.10Fixed In1.12.11CVECVE-2026-5439CERT/CCVU#536588.7

Description

A crafted ZIP archive with a forged uncompressed size can cause the server to allocate large buffers and exhaust system memory.

Impact

  • Denial of service.

Mitigation

Update Orthanc to version 1.12.11 or later.

References

How We Can Help

Who We Are

The security researchers behind this advisory.

Dr. Simon Weber Profile

Dr. rer. nat. Simon Weber

Senior Pentester & MedSec Researcher

I evaluate your SaMD with the same industry-defining security insight I contributed to the BAK MV for the revision of the B3S standard.

  • PhD on Hospital Cybersecurity
  • Critical vulnerabilities found in hospital systems
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Volker Schönefeld Profile

Dipl.-Inf. Volker Schönefeld

Senior Application Security Expert

As a former CTO and developer turned pentester, I work alongside your team to uncover vulnerabilities and find solutions that fit your architecture.

  • 20+ years as CTO, 50M+ app downloads
  • Architected and secured large-scale IoT fleets
  • Certified Web Exploitation Specialist
  • gematik Security Hero

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