Medium severity · published Mar 31, 2021
CVE-2021-23984
A malicious extension could have opened a popup window lacking an address bar
6.5
CVSS
1.1%
EPSS
No
On KEV
Description
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. This vulnerability affects Firefox ESR < 78.9, Firefox < 87, and Thunderbird < 78.9.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
None
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)1.1% · higher than 66% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FI
Firefox · Mozilla
before 87.0 · source: NVD
FE
Firefox Esr · Mozilla
before 78.9 · source: NVD
TH
Thunderbird · Mozilla
before 78.9 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-23984
CVE.org
https://www.cve.org/CVERecord?id=CVE-2021-23984
Issue Tracking
https://bugzilla.mozilla.org/show_bug.cgi?id=1693664
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2021-10/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2021-11/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2021-12/
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