What is CVE-2026-33426?

CVE-2026-33426 is a low-severity vulnerability in Discourse, classified under Missing Authorization. CVSS score: 3.5/10. Published 2026-03-21.

How severe is CVE-2026-33426?

Low severity. CVSS v3 base score is 3.5 out of 10.

Auth bypass in Discourse

CVE-2026-33426

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, users with tag-editing permissions could edit and create synonyms for tags hidden in restricted tag groups, even if they lacked visibility into those tags. 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: 0.002 (5.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 3.5 (Low). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:L/I:L/A:N.

Affected products

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

Weakness classification (CWE)

CWE-862 — Missing Authorization

References

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

Frequently asked questions

What is CVE-2026-33426?: CVE-2026-33426 is a low-severity vulnerability in Discourse, classified under Missing Authorization. CVSS score: 3.5/10. Published 2026-03-21.
How severe is CVE-2026-33426?: Low severity. CVSS v3 base score is 3.5 out of 10.