XSS in Drupal

CVE-2017-6927

Drupal 8.4.x versions before 8.4.5 and Drupal 7.x versions before 7.57 has a Drupal.checkPlain() JavaScript function which is used to escape potentially dangerous text before outputting it to HTML (as JavaScript output does not typically go through Twig autoescaping). This function does not correctly handle all methods of injecting malicious HTML, leading to a cross-site scripting vulnerability under certain circumstances. The PHP functions which Drupal provides for HTML escaping are not affected.

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.016 (74.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2017-6927?
CVE-2017-6927 is a medium-severity vulnerability in Drupal, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2018-03-01.
How severe is CVE-2017-6927?
Medium severity. CVSS v3 base score is 6.1 out of 10.