WordPress users with the Advanced Custom Fields plugin on their website should upgrade after the discovery of a vulnerability in the code that could open up sites and their visitors to cross-site scripting (XSS) attacks.
A warning from Patchstack about the flaw claimed there are more than two million active installs of the Advanced Custom Fields and Advanced Custom Fields Pro versions of the plugins, which are used to give site operators greater control of their content and data.
Patchstack researcher Rafie Muhammad uncovered the vulnerability on May 2, and reported it to Advanced Custom Fields’ vendor Delicious Brains, which took over the software last year from developer Elliot Condon.
On May 5, a month after a patched version of the plugins was released by Delicious Brains, Patchstack published details of the flaw. It’s recommended users update their plugin to at least version 6.1.6.
The flaw, tracked as CVE-2023-30777 and with a CVSS score of 6.1 out of 10 in severity, leaves sites vulnerable to reflected XSS attacks, which involve miscreants injecting malicious code into webpages. The code is then “reflected” back and executed within the browser of a visitor.
Essentially, it allows someone to run JavaScript within another person’s view of a page, allowing the attacker to do things like steal information from the page, perform actions as the user, and so on. That’s a big problem if the visitor is a logged-in administrative user, as their account could be hijacked to take over the website.
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