What is CVE-2026-27151?

CVE-2026-27151 is a low-severity vulnerability in Discourse, classified under Missing Authorization. CVSS score: 2.7/10. Published 2026-02-26.

How severe is CVE-2026-27151?

Low severity. CVSS v3 base score is 2.7 out of 10.

Auth bypass in Discourse

CVE-2026-27151

Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, the `move_posts` action only checked `can_move_posts?` on the source topic but never validated write permissions on the destination topic. This allowed TL4 users and category group moderators to move posts into topics in categories where they lack posting privileges (e.g., read-only categories or categories with group-restricted write access). 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: 0.002 (5.1th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 2.7 (Low). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:L/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-2026-27151?: CVE-2026-27151 is a low-severity vulnerability in Discourse, classified under Missing Authorization. CVSS score: 2.7/10. Published 2026-02-26.
How severe is CVE-2026-27151?: Low severity. CVSS v3 base score is 2.7 out of 10.