What is CVE-2021-39161?

CVE-2021-39161 is a medium-severity vulnerability in Discourse, classified under Cross-site Scripting. CVSS score: 4.4/10. Published 2021-08-26.

How severe is CVE-2021-39161?

Medium severity. CVSS v3 base score is 4.4 out of 10.

XSS in Discourse

CVE-2021-39161

Discourse is an open source platform for community discussion. In affected versions category names can be used for Cross-site scripting(XSS) attacks. This is mitigated by Discourse's default Content Security Policy and this vulnerability only affects sites which have modified or disabled or changed Discourse's default Content Security Policy have allowed for moderators to modify categories. This issue is patched in the latest stable, beta and tests-passed versions of Discourse. Users are advised to ensure that the Content Security Policy is enabled, and has not been modified in a way which would make it more vulnerable to XSS attacks.

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.004 (33.9th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 4.4 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N.

Affected products

Discourse — versions 2.8.0, >= 2.8.0.beta1, < 2.8.0.beta4, < 2.7.8

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

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

Frequently asked questions

What is CVE-2021-39161?: CVE-2021-39161 is a medium-severity vulnerability in Discourse, classified under Cross-site Scripting. CVSS score: 4.4/10. Published 2021-08-26.
How severe is CVE-2021-39161?: Medium severity. CVSS v3 base score is 4.4 out of 10.