Resource exhaustion in Orthanc Dicom Server
CVE-2026-5438
A gzip decompression bomb vulnerability exists when Orthanc processes HTTP request with `Content-Encoding: gzip`. The server does not enforce limits on decompressed size and allocates memory based on attacker-controlled compression metadata. A specially crafted gzip payload can trigger excessive memory allocation and exhaust system memory.
Published · last modified .
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: 0.005 (41.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 41st percentile — 41.4% 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: 0.005 · change: -0.003
Affected products
- Orthanc Dicom Server — versions 0
- Orthanc-Server Orthanc
Weakness classification (CWE)
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-2026-5438?
- CVE-2026-5438 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-2026-5438?
- High severity. CVSS v3 base score is 7.5 out of 10.