CVE-2023-29196 HTML injection via topic embedding in Discourse
Attackers can hijack user sessions via HTML injection in embedded topics if custom features are enabled and CSP is bypassed.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2023-29196?
CVE-2023-29196 is a medium-severity cross-site scripting vulnerability in Discourse Discourse, published on 18 Apr 2023. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Discourse is an open source platform for community discussion. This vulnerability is not exploitable on the default install of Discourse. A custom feature must be enabled for it to work at all, and the attacker’s payload must pass the CSP to be executed. However, if an attacker succeeds in embedding Javascript that does pass the CSP, it could result in session hijacking for any users that view the attacker’s post. The vulnerability is patched in the latest tests-passed, beta and stable branches. Users are advised to upgrade. Users unable to upgrade should enable and/or restore your site's CSP to the default one provided with Discourse. Remove any embed-able hosts configured.
Weakness: CWE-79
Which versions are affected by CVE-2023-29196?
1 open source package ship an affected version, including discourse. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
discourse Bitnami | All versions | 3.1.0 |
Products include Discourse Discourse.
How do I fix CVE-2023-29196?
Upgrade discourse to 3.1.0 or later.
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-2023-29196 being exploited?
There is no known exploitation of CVE-2023-29196 in the wild and no public exploit code.
Other vulnerabilities in Discourse Discourse
- CVE-2021-41163 RCE via malicious SNS subscription payload
- CVE-2022-36066 Discourse vulnerable to RCE via admins uploading maliciously zipped file
- CVE-2022-39356 Discourse user account takeover via email and invite link
- CVE-2023-22468 Discourse vulnerable to Cross-site Scripting in local oneboxes
- CVE-2026-27934 Discourse leaks private topic title and post excerpt via user action API endpoint
Sources
Also known as BIT-discourse-2023-29196, GHSA-986p-4x8q-8f48.