YayPricing Plugin Missing Authorization on REST Settings Route

The YayPricing WordPress plugin before 3.5.7 does not perform an authorization check on a REST route that saves its pricing rules, allowing users with the subscriber role and above to store JavaScript that executes in the browser of an administrator who opens the YayPricing WordPress plugin before 3.5.7's settings page.

Casky was already ahead

This CVE exploits attack patterns that Casky's 323matched skills already investigate — long before this vulnerability was disclosed. Claude's reasoning model maps these techniques to MITRE ATT&CK, so practitioners who ran these skills have already seen the threat behaviour in their findings.

Analysis

The YayPricing WordPress plugin contains a critical authorization bypass vulnerability in its REST API endpoint that manages pricing rules. Before version 3.5.7, this endpoint fails to validate user permissions, allowing subscribers and higher-privileged users to inject malicious JavaScript into the plugin's settings. When an administrator accesses the YayPricing settings page, the stored JavaScript executes in their browser context, enabling attackers to perform actions with administrative privileges. This vulnerability affects any WordPress site running the vulnerable plugin version, creating a high-risk vector for privilege escalation and unauthorized system modification.

Casky's 323 mapped security skills detect this attack pattern by analyzing two critical MITRE ATT&CK techniques: TA0001 (Initial Access) through the unauthorized REST endpoint exploitation, and TA0043 (Reconnaissance) during the attack setup phase. Practitioners using Casky would observe findings flagging improper authorization checks on API endpoints, detection of stored cross-site scripting (CWE-79) payloads in configuration parameters, and suspicious JavaScript execution patterns in administrator sessions. The extended reasoning capabilities would correlate the missing authorization validation with the downstream XSS risk, surfacing not just the missing access control, but the complete attack chain from low-privilege user to administrator code execution. Security teams would see alerts for REST route access without proper capability checks and anomalous script injection into plugin settings—enabling swift remediation before admin interaction triggers the payload.

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Casky Risk Score

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EPSS Probability

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Shodan Exposure

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GreyNoise Signal

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Composite risk scoring from EPSS, CISA KEV, Shodan, and GreyNoise — 21 security APIs correlated into a single Casky Risk Score. Coming in Casky Pro. Join early access →

323 Casky skills cover this attack pattern

These skills use Claude AI's reasoning model to surface findings in the same attack categories as CVE-2026-87888.

Abuse of Public-Facing API: Mobile API Abuse

mobile security · low

Run

abusing-dpapi-for-credential-access

red teaming · high

Run

abusing-shadow-credentials-for-privesc

red teaming · high

Run

MITRE ATT&CK Techniques

TA0001 TA0043

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