Buffer overflow in Orthanc Dicom Server
CVE-2026-5442
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.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.006 (48.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 48th percentile — 48.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.009 · newest: 0.006 · 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-2026-5442?
- CVE-2026-5442 is a critical-severity vulnerability in Orthanc Dicom Server, classified under Out-of-bounds Write. CVSS score: 9.8/10. Published 2026-04-09.
- How severe is CVE-2026-5442?
- Critical severity. CVSS v3 base score is 9.8 out of 10.