Quantum Secular Labs / Blog / Advisories
CVE-2026-16940: The Custom Fields WordPress plugin before 1.5.1 does not validate a user-supplied file path before deletion…
CVE-2026-16940 is rated critical with a CVSS v3.1 base score of 10.0. Per its scoring, it can be exploited over the network, without authentication, without any user interaction.
Vulnerability description
The Custom Fields WordPress plugin before 1.5.1 does not validate a user-supplied file path before deletion, allowing unauthenticated users to delete arbitrary files on the server (such as wp-config.php), which can lead to a full site takeover.
Severity breakdown
CVSS v3.1 10.0: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/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: Changed. Impact reaches beyond the vulnerable component to other resources.
- Confidentiality impact: None. No loss of confidentiality.
- 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-22: Improper Limitation of a Pathname to a Restricted Directory
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.