CVE-2026-5439
Received Received - Intake
Memory Exhaustion in Orthanc ZIP Processing via Forged Metadata

Publication date: 2026-04-09

Last updated on: 2026-04-15

Assigner: CERT/CC

Description
A memory exhaustion vulnerability exists in ZIP archive processing. Orthanc automatically extracts ZIP archives uploaded to certain endpoints and trusts metadata fields describing the uncompressed size of archived files. An attacker can craft a small ZIP archive containing a forged size value, causing the server to allocate extremely large buffers during extraction.
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Meta Information
Published
2026-04-09
Last Modified
2026-04-15
Generated
2026-06-16
AI Q&A
2026-04-09
EPSS Evaluated
2026-06-15
NVD
CVE-2026-5439
EUVD
EUVD-2026-20916
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
orthanc-server orthanc to 1.12.11 (exc)
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Exploitability
CWE
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KEV
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CWE ID Description
CWE-770 The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.
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Executive Summary

This vulnerability is a memory exhaustion issue in the processing of ZIP archives by Orthanc. When Orthanc automatically extracts ZIP archives uploaded to certain endpoints, it relies on metadata fields that describe the uncompressed size of the files inside the archive. An attacker can create a small ZIP archive with a forged size value that is much larger than the actual content, causing the server to allocate very large buffers during extraction.

Impact Analysis

The impact of this vulnerability is that an attacker can cause the server to allocate excessive memory resources by submitting a crafted ZIP archive. This can lead to memory exhaustion, potentially causing the server to slow down, crash, or become unresponsive, resulting in a denial of service.

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