CVE-2026-5443 Heap Buffer Overflow in DICOM Image Decoder (Palette Color Decode)
An attacker can trigger a heap buffer overflow in the DICOM decoder via integer overflow, potentially leading to code execution or service disruption.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-5443?
CVE-2026-5443 is a critical memory corruption vulnerability in Orthanc DICOM Server, published on 9 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A heap buffer overflow vulnerability exists during the decoding of `PALETTE COLOR` DICOM images. Pixel length validation uses 32-bit multiplication for width and height calculations. If these values overflow, the validation check incorrectly succeeds, allowing the decoder to read and write to memory beyond allocated buffers.
Weakness: CWE-787
Which versions are affected by CVE-2026-5443?
It affects 1 product.
Products include Orthanc-Server Orthanc.
How do I fix CVE-2026-5443?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-5443 being exploited?
There is no known exploitation of CVE-2026-5443 in the wild and no public exploit code.
Other vulnerabilities in Orthanc DICOM Server
- CVE-2026-5442 Heap Buffer Overflow in DICOM Image Decoder via VR UL Dimensions
- CVE-2025-0896 Orthanc Server Missing Authentication for Critical Function
- CVE-2026-5445 Out-of-Bounds Read in DicomImageDecoder (DecodeLookupTable)
- CVE-2023-33466 Path traversal in n/a
- CVE-2026-5437 Out-of-Bounds Read in DicomStreamReader
Sources
Also known as DEBIAN-CVE-2026-5443, GHSA-x69c-qfxw-mhm7, UBUNTU-CVE-2026-5443.