Information disclosure in Discourse

CVE-2026-45780

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.

Vulnerability class: Information Disclosure

Published · last modified .

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.005 (40.7th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 41st percentile — 40.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-45780: held from 0.005 to 0.005.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000

Affected products

  • Discourse — versions >= 2026.5.0-latest, < 2026.5.1, >= 2026.4.0-latest, < 2026.4.2, 2026.6.0

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-45780?
CVE-2026-45780 is a medium-severity vulnerability in Discourse, classified under Information Disclosure. CVSS score: 5.3/10. Published 2026-07-09.
How severe is CVE-2026-45780?
Medium severity. CVSS v3 base score is 5.3 out of 10.