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Findings

Vulnerability · CVE-2026-5438

A gzip decompression bomb vulnerability exists when Orthanc processes HTTP request with .

Published Apr 9, 2026 · corrected/updated Jun 17, 2026 · orthanc-server orthanc · evidence confidence high

A gzip decompression bomb vulnerability exists when Orthanc processes HTTP request with . The server does not enforce limits on decompressed size and allocates memory based on attacker-controlled compression metadata. A specially crafted gzip payload can trigger excessive memory allocation and exhaust system memory.

Grounded briefings

Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.

Executive

CVE-2026-5438 is a high public vulnerability record for orthanc-server orthanc. It is not currently listed in the CISA Known Exploited catalog. Check the linked vendor or CERT advisories for patch status. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.

System administrator

Identify whether orthanc-server orthanc is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: orthanc-server/orthanc. Check the linked vendor or CERT advisories for patch status. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.

Security analyst

Signals on file: CVSS 7.5, EPSS 0.8%. It is not currently listed in the CISA Known Exploited catalog. Weakness classes: CWE-770. Sources contributing to this record: cve_org, epss, nvd. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.

Exploitation and remediation

  • Exploitation evidence

    Not listed as known exploited in CISA KEV. Not in CISA KEV or VulnCheck KEV.

  • Patch and remediation

    No required-action text is stored yet. Use the vendor or CERT links in Sources for patch availability.

  • Safe detection guidance

    Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Apr 9, 2026 · NIST NVD

    Detected

    A gzip decompression bomb vulnerability exists when Orthanc processes HTTP request with . The server does not enforce limits on decompressed size and allocates memory based on attacker-controlled compression metadata. A specially crafted gzip payload can trigger excessive memory allocation and exhaust system memory.

  2. Jun 17, 2026 · NIST NVD

    Updated

    A gzip decompression bomb vulnerability exists when Orthanc processes HTTP request with . The server does not enforce limits on decompressed size and allocates memory based on attacker-controlled compression metadata. A specially crafted gzip payload can trigger excessive memory allocation and exhaust system memory.

Affected

  • cpe orthanc-server/orthancversion unspecified

Sources

  • CVE.orgVulnerability recordCVE-2026-5438

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-5438

    30-day exploitation probability 0.8%

    first.org
  • NIST NVDVulnerability recordCVE-2026-5438

    A gzip decompression bomb vulnerability exists when Orthanc processes HTTP request with . The server does not enforce limits on decompressed size and allocates memory based on attacker-controlled compression metadata. A specially crafted gzip payload can t

    nvd.nist.gov

References