Memory Exhaustion via Forged ZIP Metadata
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA. Impact type from CWE-770.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2026-5439
- 2026-10-03 Alias added: GHSA-6cmv-pvcc-pf5h
- 2026-10-25 EPSS moved to the below the 50th percentile
- 2026-10-25 Priority changed: MEDIUM → LOW
References
More Orthanc vulnerabilities
- TI-2025-00759 Orthanc Server Missing Authentication for Critical Function CVSS 4.0CRITICAL 9.2
- TI-2026-04766 Heap Buffer Overflow in DICOM Image Decoder (Palette Color Decode) CVSS 3.1CRITICAL 9.8
- TI-2026-04765 Heap Buffer Overflow in DICOM Image Decoder via VR UL Dimensions CVSS 3.1CRITICAL 9.8
- TI-2023-16538 Orthanc before 1.12.0 allows authenticated users with access to the Orthanc API to… CVSS 3.1HIGH 8.8
- TI-2026-04768 Out-of-Bounds Read in DicomImageDecoder (DecodeLookupTable) CVSS 3.1CRITICAL 9.1
- TI-2026-04763 Memory Exhaustion via Unbounded Content-Length CVSS 3.1HIGH 7.5
Sources
- CVE-2026-5439 · CVE Program
- CVE-2026-5439 · NVD
- FIRST EPSS
- GHSA-6cmv-pvcc-pf5h · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences