Security

The org’s staying mum on the details, but Wednesday’s fixes reach back to unsupported 8.9 branches

Updated: If you use Drupal, get ready to patch without delay. The org behind the popular open source content management system is warning of a highly critical vulnerability in Drupal core that is serious enough for it to tell users ahead of Wednesday’s patch release to set aside time to install the fix immediately.

The Drupal Security Team’s Monday PSA announcing the imminent patch for Drupal core doesn’t include any specifics, with the PSA noting that Drupal isn’t willing to share additional information until the announcement is made alongside the patch release. That, says Drupal, will happen at some point between 1700 and 2100 UTC on Wednesday, May 20. 

To reiterate, this vulnerability is found in Drupal core, the bare-bones version of Drupal designed for developers, and not Drupal CMS, the preconfigured version for those who want Drupal but don’t have coding skills.

Drupal noted that sites using Drupal Steward, its paid web application firewall service, are protected against known attack vectors, though it still recommends Steward customers update their core instances in case additional exploit methods emerge.

“The Drupal Security Team urges you to reserve time for core updates at that time because exploits might be developed within hours or days,” the advisory warns. Drupal also recommends users update to the latest supported release prior to Wednesday’s patch “so that you can address any other upgrade issues before the security window."

While it won’t get specific on the nature of the vulnerability, Drupal did share its severity score based on NIST’s standard scoring methodology, and it’s not good: The bug scored 20 out of a max of 25 on that scale, as defined by Drupal’s own documentation. 

More specifically, it’s trivially easy to leverage, doesn’t require any privilege level to exploit, could make all non-public data on an affected site accessible to the attacker, and could allow an attacker to modify or delete whatever they wanted. The only two things preventing it from scoring a perfect 25/25 are the fact that a known exploit doesn’t exist yet and that it doesn’t affect all configurations, only those using “uncommon module configurations.” 

Drupal noted that security releases will be published on Wednesday for all currently supported core branches (11.3.x, 11.2.x, 10.6.x, and 10.5.x), as well as unsupported Drupal 11.1.x and 10.4.x branches for sites that have not yet upgraded from older 10.x and 11.x releases. Drupal users on 8.9 and 9.5 are also getting patches “given the potential severity of this issue,” though the advisory warns 8.9 and 9.5 users will need to install those updates manually, which “might introduce other bugs or regressions,” leading Drupal to recommend a full upgrade to a supported core branch. 

“Drupal 8 and 9 include numerous other, previously disclosed, security vulnerabilities that will not be addressed by either Drupal Steward or the best-effort patch files,” the advisory said. Drupal 7 users are safe. 

Given the fact that not all Drupal core environments will be affected, the advisory recommends all Drupal core users set aside time on Wednesday to determine whether they’re part of the vulnerable class, and take action immediately if so. ®

Updated to add on May 20: