Executive brief
Perfmatters, a WordPress plugin used to improve website performance, contains a security vulnerability that allows attackers to inject malicious scripts into the site. If a site administrator or visitor interacts with a specially crafted link or page, the attacker could execute code in their browser. This could lead to unauthorized actions, such as redirecting users to malicious websites or stealing sensitive session information.
Technical details
A Cross-Site Scripting (XSS) vulnerability exists in the Perfmatters plugin for WordPress (versions 2.6.4 and earlier) due to improper neutralization of user-supplied input during web page generation (CWE-79). The flaw allows an unauthenticated remote attacker to inject malicious scripts into the application. Successful exploitation requires a victim (typically a privileged user) to perform an action, such as clicking a malicious link or visiting a crafted page. Once executed, the attacker's script can perform actions on behalf of the user, access cookies, or redirect the browser. The issue is resolved in version 2.6.5.
Affected products
- forgemedia LLC perfmatters <= 2.6.4
Timeline
- 2026-06-23: disclosed: Reported by researcher daroo
- 2026-06-30: advisory: Patchstack advisory published
- 2026-07-02: patched: NVD publication and confirmation of fix in 2.6.5