Backdrop Cms Cross-site Scripting

Backdrop CMS version 1.23.0 was discovered to contain a stored cross-site scripting (XSS) vulnerability via the Page content. (2022-11-23, CVE-2022-42095)

Backdrop CMS version 1.23.0 was discovered to contain a stored cross-site scripting (XSS) vulnerability via Post content. (2022-11-21, CVE-2022-42096)

An issue was discovered in Backdrop CMS 1.13.x before 1.13.5 and 1.14.x before 1.14.2. It doesn't sufficiently filter output when displaying certain block descriptions created by administrators. An attacker could potentially craft a specialized description, then have an administrator execute scripting when configuring a layout, aka XSS. This issue is mitigated by the fact that the attacker would be required to have the permission to create custom blocks, which is typically an administrative task. (2019-12-19, CVE-2019-19901)

An issue was discovered in Backdrop CMS 1.13.x before 1.13.5 and 1.14.x before 1.14.2. It doesn't sufficiently filter output when displaying content type names in the content creation interface. An attacker could potentially craft a specialized content type name, then have an editor execute scripting when creating content, aka XSS. This vulnerability is mitigated by the fact that an attacker must have a role with the "Administer content types" permission. (2019-12-19, CVE-2019-19900)

An issue was discovered in Backdrop CMS 1.14.x before 1.14.2. It doesn't sufficiently filter output when displaying file type descriptions created by administrators. An attacker could potentially craft a specialized description, then have an administrator execute scripting when viewing the list of file types, aka XSS. This vulnerability is mitigated by the fact that an attacker must have a role with the "Administer file types" permission. (2019-12-19, CVE-2019-19903)

Backdrop CMS version 1.11.0 and earlier contains a Cross Site Scripting (XSS) vulnerability in Sanitization of custom class names used on blocks and layouts. that can result in Execution of JavaScript from an unexpected source.. This attack appear to be exploitable via A user must be directed to an affected page while logged in.. This vulnerability appears to have been fixed in 1.11.1 and later. (2018-12-20, CVE-2018-1000813)

Cross site scripting is an attack where a web page executes code that is injected by an adversary. It usually appears, when users input is presented. This attack can be used to impersonate a user, take over control of the session, or even steal API keys.

The attack can be executed e.g. when you application injects the request parameter directly into the HTML code of the page returned to the user:

https://server.com/confirmation?message=Transaction+Complete

what results in:

<span>Confirmation: Transaction Complete</span>

In that case the message can be modified to become a valid Javascript code, e.g.:

https://server.com/confirmation?message=<script>dangerous javascript code here</script>

and it will be executed locally by the user's browser with full access to the user's personal application/browser data:

<span>Confirmation: <script>dangerous javascript code here</script></span>