CVE-2026-27154 Discourse has XSS when editing a malicious post
Attackers can execute arbitrary scripts via malicious user names in Discourse when specific display settings are enabled, potentially compromising user accounts.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-27154?
CVE-2026-27154 is a low-severity cross-site scripting vulnerability in Discourse Discourse, published on 26 Feb 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, a user full name can be evaluated as raw HTML when the following settings are set: `display_name_on_posts` => true; and `prioritize_username_in_ux` => false. Editing a post of a malicious user would trigger an XSS. Versions 2025.12.2, 2026.1.1, and 2026.2.0 patch the issue. No known workarounds are available.
Weakness: CWE-79
Which versions are affected by CVE-2026-27154?
1 open source package ship an affected version, including discourse. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
discourse Bitnami | All versions | 2025.12.2, 2026.1.1 |
Products include Discourse Discourse.
How do I fix CVE-2026-27154?
Upgrade discourse to a fixed version for your release line: 2025.12.2 or 2026.1.1.
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-2026-27154 being exploited?
There is no known exploitation of CVE-2026-27154 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-2026-27154, GHSA-xv43-5gcp-wgw8.