CVE-2020-26210 Cross-Site Scripting in BookStack

High 7.7 Published 3 Nov 2020 Updated 4 Aug 2024

An attacker with page edit permissions can inject malicious JavaScript that executes when other users view the page, potentially leading to session hijacking or data theft.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Over the internet
Victim action needed: A user has to click or open something
Fix: None listed

What is CVE-2020-26210?

CVE-2020-26210 is a high-severity cross-site scripting vulnerability in BookStackApp BookStack, published on 3 Nov 2020. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

Official description

In BookStack before version 0.30.4, a user with permissions to edit a page could add an attached link which would execute untrusted JavaScript code when clicked by a viewer of the page. Dangerous content may remain in the database after this update. If you think this could have been exploited the linked advisory provides a SQL query to test. As a workaround, page edit permissions could be limited to only those that are trusted until you can upgrade although this will not address existing exploitation of this vulnerability. The issue is fixed in version 0.30.4.

Weakness: CWE-79

Which versions are affected by CVE-2020-26210?

It affects 1 product.

Products include Bookstackapp Bookstack.

How do I fix CVE-2020-26210?

No fix has been published for CVE-2020-26210 yet. Limit exposure of the affected software until one is available.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2020-26210 being exploited?

There is no known exploitation of CVE-2020-26210 in the wild and no public exploit code.

Sources

Also known as GHSA-7p2j-4h6p-cq3h, GHSA-vmfp-7cw6-345x.