Drupal 10.5.x < 10.5.12 / 10.6.x < 10.6.11 / 11.2.x < 11.2.14 / 11.3.x < 11.3.12 Multiple Vulnerabilities (drupal-2026-06-17)

critical Nessus Plugin ID 321519

Synopsis

A PHP application running on the remote web server is affected by multiple vulnerabilities.

Description

According to its self-reported version, the instance of Drupal running on the remote web server is 10.5.x prior to 10.5.12, 10.6.x prior to 10.6.11, 11.2.x prior to 11.2.14, or 11.3.x prior to 11.3.12. It is, therefore, affected by multiple vulnerabilities.

- 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. This issue is mitigated by the fact that in order for it to be exploitable, a separate vulnerability must be present to allow an attacker to pass unsafe input to unserialize(). (CVE-2026-55804)

- Drupal core ships a rebuild.php front controller that can be used to rebuild Drupal (clearing the caches and rebuilding the container) when the site is in an unexpected condition. This script doesn't correctly check the Host header against the list of trusted host patterns. This could result in cache poisoning or a redirect to an attacker-controlled domain. (CVE-2026-55806)

- The JSON:API and REST modules allow you to upload image files to image fields. The validation rules check the file extension of the uploaded file but not the file MIME type. This may allow a malicious user to upload a file that is not an image. Certain web-server configurations may serve the uploaded file with its actual MIME type rather than an image type. This may lead to cross-site scripting (XSS) or other unexpected behavior. (CVE-2026-55808)

- The Media module comes with support for oEmbed. The oEmbed specification contains two discovery mechanisms, via providers.json and via URL discovery. The URL discovery code could be leveraged to trick Drupal into making server-side requests to any URL. (CVE-2026-55807)

- SA-CORE-2019-003 added protection for fields that store serialized data to disallow direct writes via web services. The above fix did not cover all potential attack vectors for JSON:API. An attacker with appropriate JSON:API write permission could potentially inject a malicious payload in certain rare circumstances, potentially resulting in PHP Object Injection. This vulnerability is mitigated by the fact that in order to be exploitable: A site must use an entity reference field type that stores a serialized property. An attacker must have permission to write to the entity via JSON:API. No field type shipped with Drupal core meets these criteria, and contributed or user-created field types that do appear to be extremely unusual. This update protects all such fields; no changes are required in contributed modules.
JSON:API is read-only by default, so sites are only affected if they have enabled write access (either through administrator configuration or the installation of a contributed or custom module that enables write access). Drupal Steward protection: This issue is being protected by Drupal Steward. In this instance, we believe that the WAF rule will provide mitigation for the common/obvious vulnerability paths, but may not cover all cases or work for all hosting providers. Additionally, several other core security advisories released today are not mitigated by Drupal Steward. Therefore, our recommended action is still to plan an actual Drupal update within 24 hours of this release. (CVE-2026-55803)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Upgrade to Drupal version 10.5.12 / 10.6.11 / 11.2.14 / 11.3.12 or later.

Plugin Details

Severity: Critical

ID: 321519

File Name: drupal_11_3_12.nasl

Version: 1.1

Type: Remote

Family: CGI abuses

Published: 6/18/2026

Updated: 6/18/2026

Configuration: Enable paranoid mode, Enable thorough checks (optional)

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3.0

CVSS v2

Risk Factor: High

Base Score: 7.5

Temporal Score: 5.5

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P

CVSS Score Source: CVE-2026-55804

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/a:drupal:drupal

Required KB Items: installed_sw/Drupal, Settings/ParanoidReport

Exploit Ease: No known exploits are available

Patch Publication Date: 6/17/2026

Vulnerability Publication Date: 6/17/2026

Reference Information

CVE: CVE-2026-55803, CVE-2026-55804, CVE-2026-55806, CVE-2026-55807, CVE-2026-55808

Detections

Analytics