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Drupal Updates CKEditor to Patch XSS Vulnerabilities

The developers of the Drupal content management system (CMS) announced on Wednesday that updates for versions 8.8.x and 8.7.x address a couple of vulnerabilities affecting the CKEditor library.

CKEditor is a popular open source WYSIWYG editor that is highly configurable and has hundreds of features. Drupal uses CKEditor and it has decided to update it to version 4.14, which patches two cross-site scripting (XSS) vulnerabilities affecting earlier versions of the library.

“Vulnerabilities are possible if Drupal is configured to use the WYSIWYG CKEditor for your site’s users. When multiple people can edit content, the vulnerability can be used to execute XSS attacks against other people, including site admins with more access,” Drupal said in an advisory.

Users have been advised to update Drupal to versions 8.8.4 or 8.7.12. Alternatively, potential attacks can be prevented by disabling the CKEditor module.

Drupal 7 is not affected, but website administrators using this version should still ensure that CKEditor has been updated to version 4.14 or higher, Drupal developers said.

While Drupal’s description of the vulnerabilities may suggest that they could pose a serious risk, they have been assigned only a “moderately critical” rating with a risk score of 13/25.

CKEditor 4.14 release notes also reveal that exploitation of the flaws involves “unlikely” or “highly unlikely” scenarios. For example, one of the weaknesses affects the HTML data processor. In order to exploit it, an attacker would have to convince the targeted user to paste malicious HTML code into the editor, either in WYSIWYG mode or source mode.

The second flaw impacts a third-party plugin named WebSpellChecker Dialog. In order to exploit it for XSS attacks, a hacker would need to convince the victim to switch CKEditor to source mode, paste malicious code, switch back to WYSIWYG mode, and preview the content on a page where the WebSpellChecker Dialog plugin files are available.

This is the first patch released by Drupal developers this year, and in 2019 they released seven rounds of security updates, including in January, February, March, April, May, July and December. While Drupal is not as targeted as WordPress, some of the vulnerabilities discovered in the past years were exploited at some point to hijack websites.

Related: Critical Drupal Vulnerability Allows Remote Code Execution

Related: Vulnerability Related to Processing of Archive Files Patched in Drupal

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Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.