Vulnerability in Mozilla Firefox

CVE-2017-7820

The "instanceof" operator can bypass the Xray wrapper mechanism. When called on web content from the browser itself or an extension the web content can provide its own result for that operator, possibly tricking the browser or extension into mishandling the element. This vulnerability affects Firefox < 56.

EPSS: 0.012 (64.7th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.

Affected products

References

Frequently asked questions

What is CVE-2017-7820?
CVE-2017-7820 is a medium-severity vulnerability in Mozilla Firefox. CVSS score: 5.3/10. Published 2018-06-11.
How severe is CVE-2017-7820?
Medium severity. CVSS v3 base score is 5.3 out of 10.