XSS in Microsoft Internet Explorer

CVE-2021-35240

A security researcher stored XSS via a Help Server setting. This affects customers using Internet Explorer, because they do not support 'rel=noopener'.

Vulnerability class: XSS (Cross-Site Scripting)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:A/AC:H/PR:H/UI:R/S:C/C:H/I:L/A:L.

EPSS exploit prediction

EPSS: 0.011 (63.6th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 64th percentile — 63.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2021-35240: held from 0.011 to 0.011.

EPSS over last 30 days · oldest: 0.011 · newest: 0.011 · change: 0.000

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2021-35240?
CVE-2021-35240 is a medium-severity vulnerability in Microsoft Internet Explorer, classified under Cross-site Scripting. CVSS score: 6.5/10. Published 2021-08-31.
How severe is CVE-2021-35240?
Medium severity. CVSS v3 base score is 6.5 out of 10.
Is CVE-2021-35240 known to be exploited?
2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.