Security features bypass in Mozilla Firefox and Firefox ESR - CVE-2021-38507

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Main Vulnerability Database Vulnerabilities #VU57881

Security features bypass in Mozilla Firefox and Firefox ESR - CVE-2021-38507

Published: November 2, 2021


Vulnerability identifier: #VU57881
CSH Severity: Low
CVSS v4: 2.1 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2021-38507
CWE-ID: CWE-254
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

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

The vulnerability exists in the Opportunistic Encryption feature of HTTP2, which allows a connection to be transparently upgraded to TLS while retaining the visual properties of an HTTP connection, including being same-origin with unencrypted connections on port 80. However, if a second encrypted port on the same IP address (e.g. port 8443) did not opt-in to opportunistic encryption; a network attacker could forward a connection from the browser from port 443 to port 8443, causing the browser to treat the content of port 8443 as same-origin with HTTP. As a result, a remote attacker can bypass Same-Origin-Policy on services hosted on other ports.


Affected software

Mozilla Firefox
Firefox ESR
Gentoo Linux
Arch Linux
SUSE CaaS Platform
SUSE Enterprise Storage
Red Hat Enterprise Linux Workstation
Red Hat Enterprise Linux Server
Red Hat Enterprise Linux Desktop
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for Power, big endian
Red Hat Enterprise Linux for Power, little endian
CentOS
Anolis OS
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for x86_64
SUSE OpenStack Cloud Crowbar
SUSE OpenStack Cloud
HPE Helion Openstack
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Red Hat Enterprise Linux for x86_64 - Extended Update Support
Red Hat Enterprise Linux for ARM 64 - Extended Update Support
Red Hat Enterprise Linux Server - TUS
Red Hat Enterprise Linux Server - AUS
SUSE Linux Enterprise Server
SUSE Linux Enterprise Server for SAP
SUSE Linux Enterprise Software Development Kit
SUSE Linux Enterprise High Performance Computing
SUSE Linux Enterprise Module for Desktop Applications
SUSE Linux Enterprise Workstation Extension
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-esr (Debian package)
thunderbird (Red Hat package)
firefox (Red Hat package)
firefox
thunderbird
MozillaFirefox
MozillaFirefox-debuginfo
MozillaFirefox-debugsource
MozillaFirefox-devel
MozillaFirefox-translations-common
MozillaFirefox-translations-other
thunderbird (Ubuntu package)
MozillaThunderbird-translations-other
MozillaThunderbird-translations-common
MozillaThunderbird-debugsource
MozillaThunderbird-debuginfo
MozillaThunderbird
thunderbird (Debian package)
mail-client/thunderbird-bin
mail-client/thunderbird
firefox (Ubuntu package)
Mozilla Thunderbird
IBM Cloud Pak for Multicloud Management Monitoring

How to mitigate CVE-2021-38507

Install updates from vendor's website.

Mozilla Firefox - update to 94.0
Firefox ESR - update to 91.3.0
Mozilla Thunderbird - update to 91.3.0
firefox-esr (Debian package) - update to 91.4.1esr-1~deb11u1
thunderbird (Red Hat package) - addressed in versions 91.3.0-2.el7_9, 91.3.0-2.el8_1, 91.3.0-2.el8_2, 91.3.0-2.el8_4
firefox (Red Hat package) - addressed in versions 91.3.0-1.el7_9, 91.3.0-1.el8_1, 91.3.0-1.el8_2, 91.3.0-1.el8_4
IBM Cloud Pak for Multicloud Management Monitoring - update to 2.3 Fix Pack 6
firefox - update to 91.3.0-1.0.1
thunderbird - update to 91.3.0-2.0.1
MozillaFirefox - addressed in versions 91.3.0-112.80.2, 91.3.0-150.6.1, 91.3.0-152.6.1
MozillaFirefox-debuginfo - addressed in versions 91.3.0-112.80.2, 91.3.0-150.6.1, 91.3.0-152.6.1
MozillaFirefox-debugsource - addressed in versions 91.3.0-112.80.2, 91.3.0-150.6.1, 91.3.0-152.6.1
MozillaFirefox-devel - addressed in versions 91.3.0-112.80.2, 91.3.0-150.6.1, 91.3.0-152.6.1
MozillaFirefox-translations-common - addressed in versions 91.3.0-112.80.2, 91.3.0-150.6.1, 91.3.0-152.6.1
MozillaFirefox-translations-other - addressed in versions 91.3.0-150.6.1, 91.3.0-152.6.1
thunderbird (Ubuntu package) - addressed in versions 1:91.3.1+build1-0ubuntu0.21.10.1, 1:91.5.0+build1-0ubuntu0.18.04.1, 1:91.5.0+build1-0ubuntu0.20.04.1
MozillaThunderbird-translations-other - update to 91.4.0-8.45.2
MozillaThunderbird-translations-common - update to 91.4.0-8.45.2
MozillaThunderbird-debugsource - update to 91.4.0-8.45.2
MozillaThunderbird-debuginfo - update to 91.4.0-8.45.2
MozillaThunderbird - update to 91.4.0-8.45.2
thunderbird (Debian package) - addressed in versions 1:91.4.1-1~deb10u1, 1:91.4.1-1~deb11u1
mail-client/thunderbird-bin - update to 91.12.0
mail-client/thunderbird - update to 91.12.0
firefox (Ubuntu package) - addressed in versions 94.0+build3-0ubuntu0.18.04.1, 94.0+build3-0ubuntu0.20.04.1, 94.0+build3-0ubuntu0.21.04.1, 94.0+build3-0ubuntu0.21.10.1

External References

Related Security Bulletins