Input validation error in Mozilla Firefox and Firefox ESR - CVE-2020-15658

Vulnerability identifier: #VU32903

CSH Severity: Low

CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear

CVE-ID: CVE-2020-15658

CWE-ID: CWE-20

Exploitation vector: Remote access

Exploit availability: No public exploit available

Affected software:
Mozilla Firefox
Firefox ESR
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for Power, big endian
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux Desktop
Red Hat Enterprise Linux Workstation
Red Hat Enterprise Linux Server
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for ARM 64 - Extended Update Support
Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
Red Hat Enterprise Linux for x86_64 - Extended Update Support
Red Hat Enterprise Linux Server - TUS
Slackware Linux
Opensuse
Ubuntu
Red Hat Enterprise Linux Server for x86_64 - Update Services for SAP Solutions
Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions
firefox (Alpine package)
firefox-esr (Alpine package)
firefox (Red Hat package)
firefox (Ubuntu package)
Mozilla Thunderbird

The vulnerability allows a remote attacker to bypass certain security restrictions.

The vulnerability exists due to insufficient validation of special characters during file download, which led to an attacker being able to cut off the file ending at an earlier position, leading to a different file type being downloaded than shown in the dialog. A remote attacker can override file type when saving data to disk.

Install updates from vendor's website.

• https://www.mozilla.org/en-US/security/advisories/mfsa2020-30/
• https://www.mozilla.org/en-US/security/advisories/mfsa2020-32/