Regular Expression Denial of Service in OpenProject's MessagesController

Regular Expression Denial of Service in OpenProject's MessagesController

CVE-2021-32763 · MEDIUM Severity

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

OpenProject is open-source, web-based project management software. In versions prior to 11.3.3, the `MessagesController` class of OpenProject has a `quote` method that implements the logic behind the Quote button in the discussion forums, and it uses a regex to strip `<pre>` tags from the message being quoted. The `(.|\s)` part can match a space character in two ways, so an unterminated `<pre>` tag containing `n` spaces causes Ruby's regex engine to backtrack to try 2<sup>n</sup> states in the NFA. This will result in a Regular Expression Denial of Service. The issue is fixed in OpenProject 11.3.3. As a workaround, one may install the patch manually.

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