CVE-2021-23984
Mozilla: Malicious extensions could have spoofed popup information
Severity
ModerateRed Hat Product Security
CVSS 3.0
Review impact separately from score.
Published · March 23, 2021
Updated · November 22, 2025
Description
The Mozilla Foundation Security Advisory describes this issue as:
A malicious extension could have opened a popup window lacking an address bar. The title of the popup lacking an address bar should not be fully controllable, but in this situation was. This could have been used to spoof a website and attempt to trick the user into providing credentials.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
No mitigation is specified in collected source.
CVSS / CWE
CVSS 3.0 · 6.1CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CWE-1021 · Improper Restriction of Rendered UI Layers or Frames