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AUSCERT External Security Bulletin Redistribution
ESB-2021.4160
MSFA Security Vulnerabilities fixed in Firefox 95
8 December 2021
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AusCERT Security Bulletin Summary
---------------------------------
Product: Firefox
Firefox ESR
Publisher: Mozilla
Operating System: Windows
UNIX variants (UNIX, Linux, OSX)
Impact/Access: Execute Arbitrary Code/Commands -- Remote with User Interaction
Cross-site Scripting -- Remote with User Interaction
Denial of Service -- Remote with User Interaction
Provide Misleading Information -- Remote with User Interaction
Access Confidential Data -- Remote with User Interaction
Reduced Security -- Remote with User Interaction
Resolution: Patch/Upgrade
CVE Names: CVE-2021-43546 CVE-2021-43545 CVE-2021-43544
CVE-2021-43543 CVE-2021-43542 CVE-2021-43541
CVE-2021-43540 CVE-2021-43539 CVE-2021-43538
CVE-2021-43537 CVE-2021-43536
Original Bulletin:
https://www.mozilla.org/en-US/security/advisories/mfsa2021-52/
https://www.mozilla.org/en-US/security/advisories/mfsa2021-53/
Comment: This bulletin contains two (2) Mozilla security advisories.
- --------------------------BEGIN INCLUDED TEXT--------------------
Mozilla Foundation Security Advisory 2021-52
Security Vulnerabilities fixed in Firefox 95
Announced: December 7, 2021
Impact: high
Products: Firefox
Fixed in: Firefox 95
# CVE-2021-43536: URL leakage when navigating while executing asynchronous
function
Reporter: Sunwoo Kim and Youngmin Kim of SNU CompSec Lab
Impact: high
Description
Under certain circumstances, asynchronous functions could have caused a
navigation to fail but expose the target URL.
References
o Bug 1730120
# CVE-2021-43537: Heap buffer overflow when using structured clone
Reporter: bo13oy of Cyber Kunlun Lab
Impact: high
Description
An incorrect type conversion of sizes from 64bit to 32bit integers allowed an
attacker to corrupt memory leading to a potentially exploitable crash.
References
o Bug 1738237
# CVE-2021-43538: Missing fullscreen and pointer lock notification when
requesting both
Reporter: Irvan Kurniawan (@sourc7)
Impact: high
Description
By misusing a race in our notification code, an attacker could have forcefully
hidden the notification for pages that had received full screen and pointer
lock access, which could have been used for spoofing attacks.
References
o Bug 1739091
# CVE-2021-43539: GC rooting failure when calling wasm instance methods
Reporter: Asumu Takikawa and Ioanna Dimitriou
Impact: high
Description
Failure to correctly record the location of live pointers across wasm instance
calls resulted in a GC occurring within the call not tracing those live
pointers. This could have led to a use-after-free causing a potentially
exploitable crash.
References
o Bug 1739683
#MOZ-2021-0010: Use-after-free in fullscreen objects on MacOS
Reporter: Atila Butkovits
Impact: high
Description
When transitioning in and out of fullscreen mode, a graphics object was not
correctly protected; resulting in memory corruption and a potentially
exploitable crash.
This bug only affects Firefox on MacOS. Other operating systems are unaffected.
References
o Bug 1735852
# CVE-2021-43540: WebExtensions could have installed persistent ServiceWorkers
Reporter: Jake Heath
Impact: moderate
Description
WebExtensions with the correct permissions were able to create and install
ServiceWorkers for third-party websites that would not have been uninstalled
with the extension.
References
o Bug 1636629
# CVE-2021-43541: External protocol handler parameters were unescaped
Reporter: chriscla
Impact: moderate
Description
When invoking protocol handlers for external protocols, a supplied parameter
URL containing spaces was not properly escaped.
References
o Bug 1696685
# CVE-2021-43542: XMLHttpRequest error codes could have leaked the existence of
an external protocol handler
Reporter: Raphael Smolik
Impact: moderate
Description
Using XMLHttpRequest, an attacker could have identified installed applications
by probing error messages for loading external protocols.
References
o Bug 1723281
# CVE-2021-43543: Bypass of CSP sandbox directive when embedding
Reporter: Armin Ebert
Impact: moderate
Description
Documents loaded with the CSP sandbox directive could have escaped the
sandbox's script restriction by embedding additional content.
References
o Bug 1738418
# CVE-2021-43544: Receiving a malicious URL as text through a SEND intent could
have led to XSS
Reporter: Irwan
Impact: moderate
Description
When receiving a URL through a SEND intent, Firefox would have searched for the
text, but subsequent usages of the address bar might have caused the URL to
load unintentionally, which could lead to XSS and spoofing attacks.
This bug only affects Firefox for Android. Other operating systems are
unaffected.
References
o Bug 1739934
# CVE-2021-43545: Denial of Service when using the Location API in a loop
Reporter: Paul Zuhlcke
Impact: low
Description
Using the Location API in a loop could have caused severe application hangs and
crashes.
References
o Bug 1720926
# CVE-2021-43546: Cursor spoofing could overlay user interface when native
cursor is zoomed
Reporter: Daniel Veditz
Impact: low
Description
It was possible to recreate previous cursor spoofing attacks against users with
a zoomed native cursor.
References
o Bug 1737751
#MOZ-2021-0009: Memory safety bugs fixed in Firefox 95 and Firefox ESR 91.4
Reporter: Mozilla developers and community
Impact: high
Description
Mozilla developers and community members Julian Hector, Randell Jesup, Gabriele
Svelto, Tyson Smith, Christian Holler, and Masayuki Nakano reported memory
safety bugs present in Firefox 94. Some of these bugs showed evidence of memory
corruption and we presume that with enough effort some of these could have been
exploited to run arbitrary code.
References
o Memory safety bugs fixed in Firefox 95
- -------------------------------------------------------------------------------
Mozilla Foundation Security Advisory 2021-53
Security Vulnerabilities fixed in Firefox ESR 91.4.0
Announced: December 7, 2021
Impact: high
Products: Firefox ESR
Fixed in: Firefox ESR 91.4
# CVE-2021-43536: URL leakage when navigating while executing asynchronous
function
Reporter: Sunwoo Kim and Youngmin Kim of SNU CompSec Lab
Impact: high
Description
Under certain circumstances, asynchronous functions could have caused a
navigation to fail but expose the target URL.
References
o Bug 1730120
# CVE-2021-43537: Heap buffer overflow when using structured clone
Reporter: bo13oy of Cyber Kunlun Lab
Impact: high
Description
An incorrect type conversion of sizes from 64bit to 32bit integers allowed an
attacker to corrupt memory leading to a potentially exploitable crash.
References
o Bug 1738237
# CVE-2021-43538: Missing fullscreen and pointer lock notification when
requesting both
Reporter: Irvan Kurniawan (@sourc7)
Impact: high
Description
By misusing a race in our notification code, an attacker could have forcefully
hidden the notification for pages that had received full screen and pointer
lock access, which could have been used for spoofing attacks.
References
o Bug 1739091
# CVE-2021-43539: GC rooting failure when calling wasm instance methods
Reporter: Asumu Takikawa and Ioanna Dimitriou
Impact: high
Description
Failure to correctly record the location of live pointers across wasm instance
calls resulted in a GC occurring within the call not tracing those live
pointers. This could have led to a use-after-free causing a potentially
exploitable crash.
References
o Bug 1739683
# CVE-2021-43541: External protocol handler parameters were unescaped
Reporter: chriscla
Impact: moderate
Description
When invoking protocol handlers for external protocols, a supplied parameter
URL containing spaces was not properly escaped.
References
o Bug 1696685
# CVE-2021-43542: XMLHttpRequest error codes could have leaked the existence of
an external protocol handler
Reporter: Raphael Smolik
Impact: moderate
Description
Using XMLHttpRequest, an attacker could have identified installed applications
by probing error messages for loading external protocols.
References
o Bug 1723281
# CVE-2021-43543: Bypass of CSP sandbox directive when embedding
Reporter: Armin Ebert
Impact: moderate
Description
Documents loaded with the CSP sandbox directive could have escaped the
sandbox's script restriction by embedding additional content.
References
o Bug 1738418
# CVE-2021-43545: Denial of Service when using the Location API in a loop
Reporter: Paul Zuhlcke
Impact: low
Description
Using the Location API in a loop could have caused severe application hangs and
crashes.
References
o Bug 1720926
# CVE-2021-43546: Cursor spoofing could overlay user interface when native
cursor is zoomed
Reporter: Daniel Veditz
Impact: low
Description
It was possible to recreate previous cursor spoofing attacks against users with
a zoomed native cursor.
References
o Bug 1737751
#MOZ-2021-0009: Memory safety bugs fixed in Firefox 95 and Firefox ESR 91.4
Reporter: Mozilla developers and community
Impact: high
Description
Mozilla developers and community members Julian Hector, Randell Jesup, Gabriele
Svelto, Tyson Smith, Christian Holler, and Masayuki Nakano reported memory
safety bugs present in Firefox 94 and Firefox ESR 91.3. Some of these bugs
showed evidence of memory corruption and we presume that with enough effort
some of these could have been exploited to run arbitrary code.
References
o Memory safety bugs fixed in Firefox 95 and Firefox ESR 91.4
- --------------------------END INCLUDED TEXT--------------------
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