Vulnerability record · CVE-2021-24000 · published 24 June 2021

CVE-2021-24000: Mozilla firefox race condition vulnerability

Mozilla · Firefox

A race condition with requestPointerLock() and setTimeout() could have resulted in a user interacting with one tab when they believed they were on a separate tab. In conjunction with certain elements (such as <input type="file">) this could have led to an attack where a user was confused about the origin of the webpage and potentially disclosed information they did not intend to. This vulnerability affects Firefox < 88.

3.1 CVSS 3.1 Low EPSS 0.61% · top 53.2% CWE-362 · Race condition

3.1CVSS 3.1 base score, v2 2.6

0.61%EPSS exploitation probability, 30 days

NoNot in CISA KEV

1Affected product versions listed by NVD

4References

17 Jun 2026Last modified by NVD

Description

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

Firefox Mozilla

References

Link	Tags
https://bugzilla.mozilla.org/show_bug.cgi?id=1694698	Issue TrackingPermissions RequiredVendor Advisory
https://www.mozilla.org/security/advisories/mfsa2021-16/	Release NotesVendor Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1694698	Issue TrackingPermissions RequiredVendor Advisory
https://www.mozilla.org/security/advisories/mfsa2021-16/	Release NotesVendor Advisory

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Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2021-24000), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.