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Findings

Vulnerability · CVE-2016-4800

eclipse jetty Improper Access Control

Published Jul 20, 2026 · corrected/updated Jul 20, 2026 · eclipse jetty · evidence confidence very high

The path normalization mechanism in PathResource class in Eclipse Jetty 9.3.x before 9.3.9 on Windows allows remote attackers to bypass protected resource restrictions and other security constraints via a URL with certain escaped characters, related to backslashes.

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-2016-4800 is a unknown public vulnerability record for eclipse jetty. CISA lists it as known exploited. Published remediation guidance: Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.

System administrator

Identify whether eclipse jetty is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: eclipse jetty. Published remediation guidance: Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable. 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: EPSS 6.4%. CISA lists it as known exploited. Sources contributing to this record: epss, vulncheck_kev. 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

    Confirmed in CISA KEV since Jul 20, 2026. Listed in CISA KEV and VulnCheck KEV.

  • Patch and remediation

    Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

  • 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. Jul 20, 2026 · VulnCheck KEV

    Detected

    The path normalization mechanism in PathResource class in Eclipse Jetty 9.3.x before 9.3.9 on Windows allows remote attackers to bypass protected resource restrictions and other security constraints via a URL with certain escaped characters, related to backslashes.

  2. Jul 20, 2026 · CISA KEV

    Known exploited

    Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

Affected

  • vendor eclipse jettyversion unspecified

Sources

  • FIRST EPSSExploitation probabilityCVE-2016-4800

    30-day exploitation probability 6.4%

    first.org
  • VulnCheck KEVConfirmed exploitationCVE-2016-4800

    The path normalization mechanism in PathResource class in Eclipse Jetty 9.3.x before 9.3.9 on Windows allows remote attackers to bypass protected resource restrictions and other security constraints via a URL with certain escaped characters, related to backslashes.

    vulncheck.com

References