CVE-2023-22489 Flarum is missing authorization in discussion replies
Attackers can bypass reply permissions and locks to post unauthorized replies in discussions where the first post was deleted, potentially enabling spam or unsolicited emails.
- 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
- Available
What is CVE-2023-22489?
CVE-2023-22489 is a low-severity missing authorization vulnerability in flarum framework, published on 13 Jan 2023. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
Flarum is a discussion platform for websites. If the first post of a discussion is permanently deleted but the discussion stays visible, any actor who can view the discussion is able to create a new reply via the REST API, no matter the reply permission or lock status. This includes users that don't have a validated email. Guests cannot successfully create a reply because the API will fail with a 500 error when the user ID 0 is inserted into the database. This happens because when the first post of a discussion is permanently deleted, the `first_post_id` attribute of the discussion becomes `null` which causes access control to be skipped for all new replies. Flarum automatically makes discussions with zero comments invisible so an additional condition for this vulnerability is that the discussion must have at least one approved reply so that `discussions.comment_count` is still above zero after the post deletion. This can open the discussion to uncontrolled spam or just unintentional replies if users still had their tab open before the vulnerable discussion was locked and then post a reply when they shouldn't be able to. In combination with the email notification settings, this could also be used as a way to send unsolicited emails. Versions between `v1.3.0` and `v1.6.3` are impacted. The vulnerability has been fixed and published as flarum/core v1.6.3. All communities running Flarum should upgrade as soon as possible. There are no known workarounds.
Weakness: CWE-862
Which versions are affected by CVE-2023-22489?
2 open source packages ship an affected version, including flarum/core. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
flarum/core Packagist | From 1.3.0 | 1.6.3 |
flarum/core Packagist | From 1.3.0 | 1.6.3 |
Products include Flarum Flarum.
How do I fix CVE-2023-22489?
Upgrade flarum/core to 1.6.3 or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2023-22489 being exploited?
There is no known exploitation of CVE-2023-22489 in the wild and no public exploit code.
Other vulnerabilities in flarum framework
- CVE-2021-32671 XSS vulnerability with translator
- CVE-2022-41938 Cross site scripting vulnerability with discussion titles in flarum
- CVE-2019-13183 Cross-site request forgery in n/a
- CVE-2023-22487 Post mentions can be used to read any post on the forum without access control
- CVE-2019-11514 Flarum mishandles invalidation of user email tokens
Sources
Also known as GHSA-hph3-hv3c-7725.