The OAuth Single Sign On – SSO (OAuth Client) plugin for WordPress operates its OAuth redirect endpoint without performing necessary capability checks. An attacker who can send HTTP requests to the site can supply a malicious redirect_url parameter, allowing the attacker to modify the global redirect URL in the database. This change can redirect legitimate users to attacker‑controlled sites, facilitating phishing or credential theft and compromising user account integrity and confidentiality.

The vulnerability impacts the WordPress plugin OAuth Single Sign On – SSO (OAuth Client) from the vendor cyberlord92. All released builds through and including version 6.26.14 are affected. Site owners running any of these versions should verify that their redirect settings have not been altered.

The CVSS score of 5.3 reflects moderate severity, while the EPSS score of less than 1% indicates a low likelihood of exploitation at present. The vulnerability is not listed in CISA's KEV catalog. Attackers can exploit the flaw by sending unauthenticated HTTP requests to the site’s OAuth redirect handler, making the attack vector straightforward and not requiring user credentials. Once the global redirect URL is modified, subsequent authenticated logins may be redirected to malicious destinations.