Security advisories for Drupal core

Drupal core contains a chain of methods that could be exploitable when an insecure deserialization vulnerability exists on the site. This so-called "gadget chain" presents no direct threat, but is a vector that can be used to achieve remote code execution or SQL injection if the application deserializes untrusted data due to another vulnerability.

This issue is not directly exploitable.

The core system module handles downloads of private and temporary files. Contrib modules can define additional kinds of files (schemes) that may also be handled by the system module.

In some cases, files may be served with the HTTP header Cache-Control: public when they should be uncacheable. This can lead to some users getting cached versions of files with information they should not be able to access. For example, files may be cached by Varnish or a CDN.

Drupal core contains a chain of methods that is exploitable when an insecure deserialization vulnerability exists on the site. This so-called "gadget chain" presents no direct threat, but is a vector that can be used to achieve remote code execution if the application deserializes untrusted data due to another vulnerability.

It is not directly exploitable.

Drupal core Link field attributes are not sufficiently sanitized, which can lead to a Cross Site Scripting vulnerability (XSS).

This vulnerability is mitigated by that fact that an attacker would need to have the ability to add specific attributes to a Link field, which typically requires edit access via core web services, or a contrib or custom module.

Sites with the Link module disabled or that do not use any link fields are not affected.