Spoofing attack in Mozilla Firefox - CVE-2021-23956
Published: January 26, 2021
Vulnerability identifier: #VU50026
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2021-23956
CWE-ID: CWE-451
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to perform spoofing attack.
The vulnerability exists due to confusing behavior of the file picker dialog. A remote attacker can trick the victim who intended to select and upload a single file into uploading a whole directory.
Affected software
Mozilla Firefox
Gentoo Linux
Arch Linux
Ubuntu
firefox (Ubuntu package)
Gentoo Linux
Arch Linux
Ubuntu
firefox (Ubuntu package)
How to mitigate CVE-2021-23956
Install updates from vendor's website.
Mozilla Firefox - update to 85.0
firefox (Ubuntu package) - addressed in versions 85.0+build1-0ubuntu0.16.04.1, 85.0+build1-0ubuntu0.18.04.1, 85.0+build1-0ubuntu0.20.04.1, 85.0+build1-0ubuntu0.20.10.1
firefox (Ubuntu package) - addressed in versions 85.0+build1-0ubuntu0.16.04.1, 85.0+build1-0ubuntu0.18.04.1, 85.0+build1-0ubuntu0.20.04.1, 85.0+build1-0ubuntu0.20.10.1