CVE-2026-45780 Discourse: Private event sample invitees are serialized to non-invited event viewers

What is CVE-2026-45780?

CVE-2026-45780 is a medium-severity vulnerability in Discourse Discourse, published on 9 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, EventSerializer could expose invited group names, sample invitees, and attendance statistics to users who could view the topic but were not entitled to view the private event invitee list. This issue is fixed in versions 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5.

Weakness: CWE-200

Which versions are affected by CVE-2026-45780?

1 open source package ship an affected version, including discourse. It affects 1 product.

Products include Discourse Discourse.

How do I fix CVE-2026-45780?

Upgrade discourse to a fixed version for your release line: 2026.1.5, 2026.4.2 or 2026.5.1.

Is CVE-2026-45780 being exploited?

There is no known exploitation of CVE-2026-45780 in the wild and no public exploit code.

Other vulnerabilities in Discourse Discourse

• CVE-2021-41163 RCE via malicious SNS subscription payload Critical 10.0
• CVE-2022-36066 Discourse vulnerable to RCE via admins uploading maliciously zipped file Critical 9.1
• CVE-2022-39356 Discourse user account takeover via email and invite link High 8.9
• CVE-2023-22468 Discourse vulnerable to Cross-site Scripting in local oneboxes High 8.8
• CVE-2026-27934 Discourse leaks private topic title and post excerpt via user action API endpoint High 8.7

All Discourse Discourse vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BIT-discourse-2026-45780, GHSA-22v7-6wgj-g9f7.