In Drupal 8.x prior to 8.3.7 When creating a view, you can optionally use Ajax to update the displayed data via filter parameters. The views subsystem/module did not restrict access to the Ajax endpoint to only views configured to use Ajax. This is mitigated if you have access restrictions on the view. It is best practice to always include some form of access restrictions on all views, even if you are using another module to display them.

In Drupal Core versions 7.x prior to 7.62, 8.6.x prior to 8.6.6 and 8.5.x prior to 8.5.9; Drupal core uses the third-party PEAR Archive_Tar library. This library has released a security update which impacts some Drupal configurations. Refer to CVE-2018-1000888 for details

In Drupal 8 prior to 8.3.4; The file REST resource does not properly validate some fields when manipulating files. A site is only affected by this if the site has the RESTful Web Services (rest) module enabled, the file REST resource is enabled and allows PATCH requests, and an attacker can get or register a user account on the site with permissions to upload files and to modify the file resource.

In Drupal 8 prior to 8.3.7; When using the REST API, users without the correct permission can post comments via REST that are approved even if the user does not have permission to post approved comments. This issue only affects sites that have the RESTful Web Services (rest) module enabled, the comment entity REST resource enabled, and where an attacker can access a user account on the site with permissions to post comments, or where anonymous users can post comments.

In versions of Drupal 8 core prior to 8.3.7; There is a vulnerability in the entity access system that could allow unwanted access to view, create, update, or delete entities. This only affects entities that do not use or do not have UUIDs, and entities that have different access restrictions on different revisions of the same entity.

Drupal core 8 before versions 8.3.4 allows remote attackers to execute arbitrary code due to the PECL YAML parser not handling PHP objects safely during certain operations.

An issue was discovered in Http Foundation in Symfony 2.7.0 through 2.7.48, 2.8.0 through 2.8.43, 3.3.0 through 3.3.17, 3.4.0 through 3.4.13, 4.0.0 through 4.0.13, and 4.1.0 through 4.1.2. It arises from support for a (legacy) IIS header that lets users override the path in the request URL via the X-Original-URL or X-Rewrite-URL HTTP request header. These headers are designed for IIS support, but it's not verified that the server is in fact running IIS, which means anybody who can send these requests to an application can trigger this. This affects \Symfony\Component\HttpFoundation\Request::prepareRequestUri() where X-Original-URL and X_REWRITE_URL are both used. The fix drops support for these methods so that they cannot be used as attack vectors such as web cache poisoning.

A remote code execution vulnerability exists within multiple subsystems of Drupal 7.x and 8.x. This potentially allows attackers to exploit multiple attack vectors on a Drupal site, which could result in the site being compromised. This vulnerability is related to Drupal core - Highly critical - Remote Code Execution - SA-CORE-2018-002. Both SA-CORE-2018-002 and this vulnerability are being exploited in the wild.

Cross-site scripting (XSS) vulnerability in the Enhanced Image (aka image2) plugin for CKEditor (in versions 4.5.10 through 4.9.1; fixed in 4.9.2), as used in Drupal 8 before 8.4.7 and 8.5.x before 8.5.2 and other products, allows remote attackers to inject arbitrary web script through a crafted IMG element.

In Drupal versions 8.4.x versions before 8.4.5 users with permission to post comments are able to view content and comments they do not have access to, and are also able to add comments to this content. This vulnerability is mitigated by the fact that the comment system must be enabled and the attacker must have permission to post comments.