CVE-2026-5437
Published: 09 April 2026
Summary
CVE-2026-5437 is a high-severity Out-of-bounds Read (CWE-125) vulnerability in Orthanc-Server Orthanc. Its CVSS base score is 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 16.3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation).
Threat & Defense at a Glance
Threat & Defense Details
Mitigating Controls (NIST 800-53 r5)AI
Directly addresses the insufficient input validation in DicomStreamReader by requiring validation of DICOM metadata inputs at system entry points to prevent out-of-bounds reads from malformed structures.
Requires timely identification, reporting, and patching of the specific out-of-bounds read flaw in DICOM meta-header parsing to eliminate the vulnerability.
Implements memory safeguards that mitigate the impact of out-of-bounds reads during DICOM parsing, reducing potential denial-of-service effects.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Remote out-of-bounds read in public-facing Orthanc DICOM server triggered by crafted network data enables exploitation of public-facing applications (T1190) resulting in endpoint denial of service via application exploitation (T1499.004).
NVD Description
An out-of-bounds read vulnerability exists in `DicomStreamReader` during DICOM meta-header parsing. When processing malformed metadata structures, the parser may read beyond the bounds of the allocated metadata buffer. Although this issue does not typically crash the server or expose data…
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directly to the attacker, it reflects insufficient input validation in the parsing logic.
Deeper analysisAI
CVE-2026-5437, published on 2026-04-09, is an out-of-bounds read vulnerability (CWE-125) in the DicomStreamReader component during DICOM meta-header parsing. The issue arises when processing malformed metadata structures, causing the parser to read beyond the bounds of the allocated metadata buffer due to insufficient input validation. This affects DICOM processing software such as Orthanc-server, as indicated by vendor references.
Remote attackers can exploit this vulnerability over the network with low complexity, requiring no privileges or user interaction (CVSS:3.1 score of 7.5; AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H). By sending crafted DICOM data with malformed metadata, an unauthenticated attacker can trigger the out-of-bounds read, resulting in high availability impact, such as potential denial of service, though the issue does not typically crash the server or directly expose data.
Mitigation details are available in related advisories, including the CERT vulnerability note at https://kb.cert.org/vuls/id/536588, as well as vendor resources at https://www.machinespirits.de/ and https://www.orthanc-server.com/.
Details
- CWE(s)