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CVE-2016-20052: Snewscms: Arbitrary file upload

CVE-2016-20052 is rated critical with a CVSS v3.1 base score of 9.8 and affects Snewscms. Per its scoring, it can be exploited over the network, without authentication, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available.

Vulnerability description

Snews CMS 1.7 contains an unrestricted file upload vulnerability that allows unauthenticated attackers to upload arbitrary files including PHP executables to the snews_files directory. Attackers can upload malicious PHP files through the multipart form-data upload endpoint and execute them by accessing the uploaded file path to achieve remote code execution.

Severity breakdown

CVSS v3.1 9.8: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

  • Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
  • Attack complexity: Low. No special conditions; the attack can be repeated reliably.
  • Privileges required: None. No account or prior access is needed.
  • User interaction: None. No action from any user is needed.
  • Scope: Unchanged. Impact stays within the vulnerable component.
  • Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
  • Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
  • Availability impact: High. Total loss of availability; the component can be shut down.

Underlying weakness

CWE-434: Unrestricted Upload of File with Dangerous Type

The product allows the upload or transfer of dangerous file types that are automatically processed within its environment.

Affected products

  • Snewscms: up to and including 1.7

References