What is CVE-2026-33427?

CVE-2026-33427 is a high-severity vulnerability in Discourse, classified under Missing Authorization. CVSS score: 7.5/10. Published 2026-03-21.

How severe is CVE-2026-33427?

High severity. CVSS v3 base score is 7.5 out of 10.

Auth bypass in Discourse

CVE-2026-33427

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, an unauthenticated attacker can cause a legitimate Discourse authorization page to display an attacker-controlled domain, facilitating social engineering attacks against users. 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 (11.2th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/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-2026-33427?: CVE-2026-33427 is a high-severity vulnerability in Discourse, classified under Missing Authorization. CVSS score: 7.5/10. Published 2026-03-21.
How severe is CVE-2026-33427?: High severity. CVSS v3 base score is 7.5 out of 10.