Vulnerability · Published Apr 9, 2026 · Assigned by certcc
CVE-2026-5442Heap Buffer Overflow in DICOM Image Decoder via VR UL Dimensions
Critical 9.8
In plain English
A critical-severity security flaw in DICOM Server from Orthanc. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 49% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | orthanc | no fix listed | DEBIAN-CVE-2026-5442 |
| Debian:13 | orthanc | no fix listed | DEBIAN-CVE-2026-5442 |
| Debian:14 | orthanc | 1.12.10+dfsg-4 | DEBIAN-CVE-2026-5442 |
| Ubuntu:22.04:LTS | orthanc | no fix listed | UBUNTU-CVE-2026-5442 |
| Ubuntu:24.04:LTS | orthanc | no fix listed | UBUNTU-CVE-2026-5442 |
| Ubuntu:25.10 | orthanc | no fix listed | UBUNTU-CVE-2026-5442 |
| Ubuntu:26.04:LTS | orthanc | no fix listed | UBUNTU-CVE-2026-5442 |
| Ubuntu:26.10 | orthanc | no fix listed | UBUNTU-CVE-2026-5442 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Orthanc | DICOM Server | 0 – through 1.12.10 |