What is CVE-2026-33428?

CVE-2026-33428 is a medium-severity vulnerability in Discourse, classified under Incorrect Authorization. CVSS score: 6.5/10. Published 2026-03-21.

How severe is CVE-2026-33428?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Auth bypass in Discourse

CVE-2026-33428

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, a non-staff user with elevated group membership could access deleted posts belonging to any user due to an overly broad authorization check on the deleted posts index endpoint. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. No known workarounds are available.

Vulnerability class: Broken Access Control

EPSS: 0.003 (19.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.

Affected products

Discourse — versions = 2026.3.0-latest, >= 2026.1.0-latest, < 2026.1.2, >= 2026.2.0-latest, < 2026.2.1

Weakness classification (CWE)

CWE-863 — Incorrect Authorization

References

security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)

Frequently asked questions

What is CVE-2026-33428?: CVE-2026-33428 is a medium-severity vulnerability in Discourse, classified under Incorrect Authorization. CVSS score: 6.5/10. Published 2026-03-21.
How severe is CVE-2026-33428?: Medium severity. CVSS v3 base score is 6.5 out of 10.