# CVE-2026-5439: A memory exhaustion vulnerability exists in ZIP archive processing. Orthanc automatically extracts ZIP archives…

Source: https://junglewise.ai/threats/cve-2026-5439-a-memory-exhaustion-vulnerability-exists-in-zip-archive-processing  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-04-09  
License: CC BY 4.0 with a link back

CVE-2026-5439 · Severity: high · CVSS 7.5 · Published 2026-04-09

A memory exhaustion vulnerability exists in ZIP archive processing. Orthanc automatically extracts ZIP archives uploaded to certain endpoints and trusts metadata fields describing the uncompressed size of archived files. An attacker can craft a small ZIP archive containing a forged size value, causing the server to allocate extremely large buffers during extraction.

Technologies: [Orthanc-Server Orthanc](https://junglewise.ai/threats/technologies/orthanc-server-orthanc). Vendors: [Orthanc-Server](https://junglewise.ai/threats/vendors/orthanc-server).

## Quick answers

**Is CVE-2026-5439 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-5439 being exploited in the wild.

**How severe is CVE-2026-5439?** High severity, with a CVSS score of 7.5, published 9 April 2026.

**Which products and versions are affected?** Orthanc-Server Orthanc. The advisory does not name versions.

**Is there a fix for CVE-2026-5439?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**Am I affected by CVE-2026-5439?** Check whether you run Orthanc-Server Orthanc. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Affected products

- Orthanc-Server Orthanc

## Related threats

- [An out-of-bounds read vulnerability exists in the `DecodeLookupTable` function within `DicomImageDecoder.cpp`. The…](https://junglewise.ai/threats/cve-2026-5445-an-out-of-bounds-read-vulnerability-exists-in-the)
- [A heap buffer overflow vulnerability exists in the PAM image parsing logic. When Orthanc processes a crafted PAM image…](https://junglewise.ai/threats/cve-2026-5444-a-heap-buffer-overflow-vulnerability-exists-in-the-pam-image)
- [A heap buffer overflow vulnerability exists during the decoding of `PALETTE COLOR` DICOM images. Pixel length…](https://junglewise.ai/threats/cve-2026-5443-a-heap-buffer-overflow-vulnerability-exists-during-the-decoding-of)
- [A heap buffer overflow vulnerability exists in the DICOM image decoder. Dimension fields are encoded using Value…](https://junglewise.ai/threats/cve-2026-5442-a-heap-buffer-overflow-vulnerability-exists-in-the-dicom-image)
- [An out-of-bounds read vulnerability exists in the `DecodePsmctRle1` function of `DicomImageDecoder.cpp`. The…](https://junglewise.ai/threats/cve-2026-5441-an-out-of-bounds-read-vulnerability-exists-in-the-decodepsmctrle1)