CVE-2021-37633 XSS via d-popover and d-html-popover attribute
Attackers can execute arbitrary scripts via popover attributes in Discourse forums if the Content Security Policy is modified or disabled.
- 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-2021-37633?
CVE-2021-37633 is a high-severity cross-site scripting vulnerability in Discourse Discourse, published on 9 Aug 2021. 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 discussion platform. In versions prior to 2.7.8 rendering of d-popover tooltips can be susceptible to XSS attacks. This vulnerability only affects sites which have modified or disabled Discourse's default Content Security Policy. This issue is patched in the latest `stable` 2.7.8 version of Discourse. As a workaround users may ensure that the Content Security Policy is enabled, and has not been modified in a way which would make it more vulnerable to XSS attacks.
Weakness: CWE-79
Which versions are affected by CVE-2021-37633?
1 open source package ship an affected version, including discourse. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
discourse Bitnami | All versions | 2.7.8 |
Products include Discourse Discourse.
How do I fix CVE-2021-37633?
Upgrade discourse to 2.7.8 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-2021-37633 being exploited?
There is no known exploitation of CVE-2021-37633 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-2021-37633, GHSA-v3v8-3m5w-pjp9.