What is CVE-2026-27154?

CVE-2026-27154 is a medium-severity vulnerability in Discourse, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-02-26.

How severe is CVE-2026-27154?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in Discourse

CVE-2026-27154

Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, a user full name can be evaluated as raw HTML when the following settings are set: `display_name_on_posts` => true; and `prioritize_username_in_ux` => false. Editing a post of a malicious user would trigger an XSS. Versions 2025.12.2, 2026.1.1, and 2026.2.0 patch the issue. No known workarounds are available.

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.002 (4.9th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/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-79 — Cross-site Scripting

References

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

Frequently asked questions

What is CVE-2026-27154?: CVE-2026-27154 is a medium-severity vulnerability in Discourse, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-02-26.
How severe is CVE-2026-27154?: Medium severity. CVSS v3 base score is 6.1 out of 10.