← Vulnerability feed

Vulnerability record · CVE-2026-5440 · published 9 April 2026

CVE-2026-5440: Orthanc-server orthanc allocation without limits vulnerability

Orthanc Server · Orthanc

A memory exhaustion vulnerability exists in the HTTP server due to unbounded use of the `Content-Length` header. The server allocates memory directly based on the attacker supplied header value without enforcing an upper limit. A crafted HTTP request containing an extremely large `Content-Length` value can trigger excessive memory allocation and server termination, even without sending a request body.

7.5 CVSS 3.1 High EPSS 0.94% · top 40.5% CWE-770 · Allocation without limits
7.5CVSS 3.1 base score
0.94%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
3References
17 Jun 2026Last modified by NVD

Description

A memory exhaustion vulnerability exists in the HTTP server due to unbounded use of the `Content-Length` header. The server allocates memory directly based on the attacker supplied header value without enforcing an upper limit. A crafted HTTP request containing an extremely large `Content-Length` value can trigger excessive memory allocation and server termination, even without sending a request body.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://kb.cert.org/vuls/id/536588 Third Party AdvisoryVDB Entry
https://www.machinespirits.de/ Not Applicable
https://www.orthanc-server.com/ Product

Track CVE-2026-5440 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2026-5442Orthanc-server orthanc out-of-bounds write vulnerabilityA heap buffer overflow vulnerability exists in the DICOM image decoder. Dimension fields are encoded using Value Representation (VR) Unsigned Long (U…EPSS 0.92%9.8CVE-2026-5443Orthanc-server orthanc out-of-bounds write vulnerabilityA heap buffer overflow vulnerability exists during the decoding of `PALETTE COLOR` DICOM images. Pixel length validation uses 32-bit multiplication f…EPSS 0.88%9.2CVE-2025-0896Orthanc-server orthanc missing authentication for critical function vulnerabilityOrthanc server prior to version 1.5.8 does not enable basic authentication by default when remote access is enabled. This could result in unauthorize…EPSS 2.5%9.1CVE-2026-5445Orthanc-server orthanc out-of-bounds read vulnerabilityAn out-of-bounds read vulnerability exists in the `DecodeLookupTable` function within `DicomImageDecoder.cpp`. The lookup-table decoding logic used f…EPSS 0.79%8.8CVE-2023-33466Orthanc-server orthanc code injection vulnerabilityOrthanc before 1.12.0 allows authenticated users with access to the Orthanc API to overwrite arbitrary files on the file system, and in specific depl…EPSS 4.2%7.5CVE-2026-5437Orthanc-server orthanc out-of-bounds read vulnerabilityAn out-of-bounds read vulnerability exists in `DicomStreamReader` during DICOM meta-header parsing. When processing malformed metadata structures, th…EPSS 0.76%7.5CVE-2026-5438Orthanc-server orthanc allocation without limits vulnerabilityA gzip decompression bomb vulnerability exists when Orthanc processes HTTP request with `Content-Encoding: gzip`. The server does not enforce limits …EPSS 0.76%7.5CVE-2026-5439Orthanc-server orthanc allocation without limits vulnerabilityA memory exhaustion vulnerability exists in ZIP archive processing. Orthanc automatically extracts ZIP archives uploaded to certain endpoints and tru…EPSS 0.76%

Source: NIST National Vulnerability Database (record CVE-2026-5440), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.