Information disclosure in Mozilla Firefox and Firefox ESR - CVE-2020-15655

Vulnerability identifier: #VU32900

CSH Severity: Medium

CVSS v4: 5.9 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2020-15655

CWE-ID: CWE-200

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to gain access to potentially sensitive information.

The vulnerability exists in the Extension APIs. A redirected HTTP request which is observed or modified through a web extension could bypass existing CORS checks, leading to potential disclosure of cross-origin information.

Mozilla Firefox
Firefox ESR
Slackware Linux
Opensuse
Ubuntu
Mozilla Thunderbird
firefox-esr (Alpine package)
firefox (Alpine package)
firefox (Ubuntu package)

Install updates from vendor's website.

Mozilla Firefox - update to 79.0
Firefox ESR - update to 78.1.0
Mozilla Thunderbird - update to 78.0.1
firefox-esr (Alpine package) - update to 78.1.0-r0
firefox (Alpine package) - update to 79.0-r0
firefox (Ubuntu package) - addressed in versions 79.0+build1-0ubuntu0.16.04.2, 79.0+build1-0ubuntu0.18.04.1, 79.0+build1-0ubuntu0.20.04.1

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

• Multiple vulnerabilities in Mozilla Firefox
• Multiple vulnerabilities in Mozilla Thunderbird
• OpenSUSE Linux update for MozillaFirefox
• OpenSUSE Linux update for MozillaFirefox
• OpenSUSE Linux update for MozillaFirefox
• Information disclosure in firefox-esr (Alpine package)
• Information disclosure in firefox (Alpine package)
• Ubuntu update for firefox