Auth bypass in Discourse

CVE-2026-27150

Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, missing `validate_before_create` authorization in Data Explorer's `QueryGroupBookmarkable` allows any logged-in user to create bookmarks for query groups they don't have access to, enabling metadata disclosure via bookmark reminder notifications. Versions 2025.12.2, 2026.1.1, and 2026.2.0 fix this issue and also make sure `validate_before_create` throws NotImplementedError in BaseBookmarkable if not implemented, to prevent similar issues in the future. No known workarounds are available.

Vulnerability class: Broken Access Control

Published · last modified .

CVSS v3 metric

CVSS v3 base score 3.8 (Low). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.003 (16.0th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 16th percentile — 16.0% 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-2026-27150: held from 0.002 to 0.003.

EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001

Affected products

  • Discourse — versions >= 2026.2.0-latest, < 2026.2.0, >= 2026.1.0-latest, < 2026.1.1, 2026.2.0

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-27150?
CVE-2026-27150 is a low-severity vulnerability in Discourse, classified under Missing Authorization. CVSS score: 3.8/10. Published 2026-02-26.
How severe is CVE-2026-27150?
Low severity. CVSS v3 base score is 3.8 out of 10.