What is CVE-2026-5439?

CVE-2026-5439 is a high-severity vulnerability in Orthanc Dicom Server, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 7.5/10. Published 2026-04-09.

How severe is CVE-2026-5439?

High severity. CVSS v3 base score is 7.5 out of 10.

Resource exhaustion in Orthanc Dicom Server

CVE-2026-5439

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.

Published 2026-04-09 · last modified 2026-10-26.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.004 (36.5th percentile), scored 2026-10-26.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 37th percentile — 36.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.008 · newest: 0.004 · change: -0.003

Affected products

Orthanc Dicom Server — versions 0
Orthanc-Server Orthanc

Weakness classification (CWE)

CWE-770 — Allocation of Resources Without Limits or Throttling

References

www.orthanc-server.com/ (Product)
www.machinespirits.de/ (Not Applicable)
kb.cert.org/vuls/id/536588 (VDB Entry, Third Party Advisory)

Frequently asked questions

What is CVE-2026-5439?: CVE-2026-5439 is a high-severity vulnerability in Orthanc Dicom Server, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 7.5/10. Published 2026-04-09.
How severe is CVE-2026-5439?: High severity. CVSS v3 base score is 7.5 out of 10.