Arch Linux Security Advisory ASA-202111-2
=========================================

Severity: High
Date    : 2021-11-05
CVE-ID  : CVE-2021-38503 CVE-2021-38504 CVE-2021-38506 CVE-2021-38507
          CVE-2021-38508 CVE-2021-38509
Package : firefox
Type    : multiple issues
Remote  : Yes
Link    : https://security.archlinux.org/AVG-2511

Summary
=======

The package firefox before version 94.0-1 is vulnerable to multiple
issues including arbitrary code execution, content spoofing, same-
origin policy bypass and sandbox escape.

Resolution
==========

Upgrade to 94.0-1.

# pacman -Syu "firefox>=94.0-1"

The problems have been fixed upstream in version 94.0.

Workaround
==========

None.

Description
===========

- CVE-2021-38503 (sandbox escape)

A security issue has been found in Firefox before version 94 and
Thunderbird before version 91.3. The iframe sandbox rules were not
correctly applied to XSLT stylesheets, allowing an iframe to bypass
restrictions such as executing scripts or navigating the top-level
frame.

- CVE-2021-38504 (arbitrary code execution)

A security issue has been found in Firefox before version 94 and
Thunderbird before version 91.3. When interacting with an HTML input
element's file picker dialog with "webkitdirectory" set, a use-after-
free could have resulted, leading to memory corruption and a
potentially exploitable crash.

- CVE-2021-38506 (content spoofing)

A security issue has been found in Firefox before version 94 and
Thunderbird before version 91.3. Through a series of navigations,
Firefox and Thunderbird could have entered fullscreen mode without
notification or warning to the user. This could lead to spoofing
attacks on the browser UI including phishing.

- CVE-2021-38507 (same-origin policy bypass)

A security issue has been found in Firefox before version 94 and
Thunderbird before version 91.3. The Opportunistic Encryption feature
of HTTP2 (RFC 8164) 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 to port 443 to port 8443,
causing the browser to treat the content of port 8443 as same-origin
with HTTP.  This was resolved by disabling the Opportunistic Encryption
feature, which had low usage.

- CVE-2021-38508 (content spoofing)

A security issue has been found in Firefox before version 94 and
Thunderbird before version 91.3. By displaying a form validity message
in the correct location at the same time as a permission prompt (such
as for geolocation), the validity message could have obscured the
prompt, resulting in the user potentially being tricked into granting
the permission.

- CVE-2021-38509 (content spoofing)

A security issue has been found in Firefox before version 94 and
Thunderbird before version 91.3. Due to an unusual sequence of
attacker-controlled events, a Javascript alert() dialog with arbitrary
(although unstyled) contents could be displayed over top an
uncontrolled webpage of the attacker's choosing.

Impact
======

A remote attacker could execute arbitrary code, spoof content or bypass
same-origin policy through crafted web content.

References
==========

https://www.mozilla.org/en-US/security/advisories/mfsa2021-48/
https://www.mozilla.org/security/advisories/mfsa2021-48/
https://www.mozilla.org/security/advisories/mfsa2021-50/
https://bugzilla.mozilla.org/show_bug.cgi?id=1729517
https://bugzilla.mozilla.org/show_bug.cgi?id=1730156
https://bugzilla.mozilla.org/show_bug.cgi?id=1730750
https://bugzilla.mozilla.org/show_bug.cgi?id=1730935
https://bugzilla.mozilla.org/show_bug.cgi?id=1366818
https://bugzilla.mozilla.org/show_bug.cgi?id=1718571
https://security.archlinux.org/CVE-2021-38503
https://security.archlinux.org/CVE-2021-38504
https://security.archlinux.org/CVE-2021-38506
https://security.archlinux.org/CVE-2021-38507
https://security.archlinux.org/CVE-2021-38508
https://security.archlinux.org/CVE-2021-38509