A flaw in twoWordPresscustom plug-ins leaves users vulnerable to cross-site scripting attacks (XSS), according to a recent report.
Patchstack researcherRafie Muhammad recently discovered an XSS flaw in theAdvanced Custom FieldsandAdvanced Custom Fields Proplug-ins, which are actively installed by over 2 million users worldwide, according toBleeping Computer.
The flaw, called CVE-2023-30777 was discovered on May 2 and was given a high-severity prominence. The plug-ins’ developer, WP Engine, quickly provided a security update, version 6.1.6, within days of learning about the vulnerability,on May 4.
The popularcustom field buildersallow users to have full control of their content management system from the back end, with WordPress edit screens, custom field data, and other features.
However, XSS bugs can be seen in a front-facing fashion and work by injecting “malicious scripts on websites viewed by others, resulting in the execution of code on the visitor’s web browser,” Bleeping Computer added.
This could leave website visitors open to having their data stolen from infected WordPress sites, Patchstack noted.
Specifics about the XSS vulnerability indicate that it might be triggered by a “default installation or configuration of the Advanced Custom Fields plug-in.” However, users would have to have logged-in access to the Advanced Custom Fields plug-in to trigger it in the first place, meaning a bad actor would have to trick someone with access to trigger the flaw, the researchers added.
The CVE-2023-30777 flaw can be found in theadmin_body_classfunction handler, in which a bad actor can inject malicious code. In particular, this bug injects DOM XSS payloads into the improperly drafted code, which is not caught by the code’s sanitize output, a security measure of sorts, which is part of the flaw.
The fix on version 6.1.6 introduced theadmin_body_class hook,which blocks the XSS attack from being able to execute.
Users ofAdvanced Custom FieldsandAdvanced Custom Fields Proshould upgrade the plug-ins to version 6.1.6 or later. Many users remain susceptible to attack, with approximately 72.1% of WordPress.org plug-in users having versions running below 6.1. This makes their websites vulnerable not only to XSS attacks but also to other flaws in the wild, the publication said.
