What is CVE-2026-27021?

CVE-2026-27021 is a medium-severity vulnerability in Discourse, classified under Missing Authorization. CVSS score: 5.3/10. Published 2026-02-26.

How severe is CVE-2026-27021?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Auth bypass in Discourse

CVE-2026-27021

Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, the voters endpoint in the poll plugin lacked post visibility checks which allowed unauthorized access to voters details of polls in any post. Versions 2025.12.2, 2026.1.1, and 2026.2.0 patch the issue. No known workarounds are available.

Vulnerability class: Broken Access Control

EPSS: 0.003 (20.2th percentile) — read the EPSS interpretation.

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.

Affected products

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

Weakness classification (CWE)

CWE-862 — Missing Authorization

References

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

Frequently asked questions

What is CVE-2026-27021?: CVE-2026-27021 is a medium-severity vulnerability in Discourse, classified under Missing Authorization. CVSS score: 5.3/10. Published 2026-02-26.
How severe is CVE-2026-27021?: Medium severity. CVSS v3 base score is 5.3 out of 10.