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AUSCERT External Security Bulletin Redistribution
ESB-2020.4082
MFSA 2020-50 Security Vulnerabilities fixed in Firefox 83
18 November 2020
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AusCERT Security Bulletin Summary
---------------------------------
Product: Mozilla Firefox
Publisher: Mozilla
Operating System: Windows
UNIX variants (UNIX, Linux, OSX)
Android
Impact/Access: Execute Arbitrary Code/Commands -- Remote with User Interaction
Increased Privileges -- 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-2020-26969 CVE-2020-26968 CVE-2020-26967
CVE-2020-26966 CVE-2020-26965 CVE-2020-26964
CVE-2020-26963 CVE-2020-26962 CVE-2020-26961
CVE-2020-26960 CVE-2020-26959 CVE-2020-26958
CVE-2020-26957 CVE-2020-26956 CVE-2020-26955
CVE-2020-26954 CVE-2020-26953 CVE-2020-26952
CVE-2020-26951 CVE-2020-16012 CVE-2020-15999
Reference: ESB-2020.4081
ESB-2020.4080
ESB-2020.3800.2
Original Bulletin:
https://www.mozilla.org/en-US/security/advisories/mfsa2020-50/
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Mozilla Foundation Security Advisory 2020-50
Security Vulnerabilities fixed in Firefox 83
Announced
November 17, 2020
Impact
high
Products
Firefox
Fixed in
Firefox 83
# CVE-2020-26951: Parsing mismatches could confuse and bypass security
sanitizer for chrome privileged code
Reporter
Irvan Kurniawan (@sourc7)
Impact
high
Description
A parsing and event loading mismatch in Firefox's SVG code could have allowed
load events to fire, even after sanitization. An attacker already capable of
exploiting an XSS vulnerability in privileged internal pages could have used
this attack to bypass our built-in sanitizer.
References
o Bug 1667113
# CVE-2020-26952: Out of memory handling of JITed, inlined functions could lead
to a memory corruption
Reporter
Gary Kwong
Impact
high
Description
Incorrect bookkeeping of functions inlined during JIT compilation could have
led to memory corruption and a potentially exploitable crash when handling
out-of-memory errors.
References
o Bug 1667685
# CVE-2020-16012: Variable time processing of cross-origin images during
drawImage calls
Reporter
Aleksejs Popovs
Impact
moderate
Description
When drawing a transparent image on top of an unknown cross-origin image, the
Skia library drawImage function took a variable amount of time depending on the
content of the underlying image. This resulted in potential cross-origin
information exposure of image content through timing side-channel attacks.
References
o Bug 1642028
# CVE-2020-26953: Fullscreen could be enabled without displaying the security
UI
Reporter
Abdulrahman Alqabandi of Microsoft Browser Vulnerability Research
Impact
moderate
Description
It was possible to cause the browser to enter fullscreen mode without
displaying the security UI; thus making it possible to attempt a phishing
attack or otherwise confuse the user.
References
o Bug 1656741
# CVE-2020-26954: Local spoofing of web manifests for arbitrary pages in
Firefox for Android
Reporter
Muneaki Nishimura
Impact
moderate
Description
When accepting a malicious intent from other installed apps, Firefox for
Android accepted manifests from arbitrary file paths and allowed declaring
webapp manifests for other origins. This could be used to gain fullscreen
access for UI spoofing and could also lead to cross-origin attacks on targeted
websites.
Note: This issue only affected Firefox for Android. Other operating systems are
unaffected.
References
o Bug 1657026
# CVE-2020-26955: Cookies set during file downloads are shared between normal
and Private Browsing Mode in Firefox for Android
Reporter
Muneaki Nishimura
Impact
moderate
Description
When a user downloaded a file in Firefox for Android, if a cookie is set, it
would have been re-sent during a subsequent file download operation on the same
domain, regardless of whether the original and subsequent request were in
private and non-private browsing modes.
Note: This issue only affected Firefox for Android. Other operating systems are
unaffected.
References
o Bug 1663261
# CVE-2020-26956: XSS through paste (manual and clipboard API)
Reporter
Irvan Kurniawan (@sourc7)
Impact
moderate
Description
In some cases, removing HTML elements during sanitization would keep existing
SVG event handlers and therefore lead to XSS.
References
o Bug 1666300
# CVE-2020-26957: OneCRL was not working in Firefox for Android
Reporter
Kevin Brosnan
Impact
moderate
Description
OneCRL was non-functional in the new Firefox for Android due to a missing
service initialization. This could result in a failure to enforce some
certificate revocations.
Note: This issue only affected Firefox for Android. Other operating systems are
unaffected.
References
o Bug 1667179
# CVE-2020-26958: Requests intercepted through ServiceWorkers lacked MIME type
restrictions
Reporter
Moti Harmats
Impact
moderate
Description
Firefox did not block execution of scripts with incorrect MIME types when the
response was intercepted and cached through a ServiceWorker. This could lead to
a cross-site script inclusion vulnerability, or a Content Security Policy
bypass.
References
o Bug 1669355
# CVE-2020-26959: Use-after-free in WebRequestService
Reporter
Bharadwaj Machiraju
Impact
moderate
Description
During browser shutdown, reference decrementing could have occured on a
previously freed object, resulting in a use-after-free, memory corruption, and
a potentially exploitable crash.
References
o Bug 1669466
# CVE-2020-26960: Potential use-after-free in uses of nsTArray
Reporter
Zijie Zhao
Impact
moderate
Description
If the Compact() method was called on an nsTArray, the array could have been
reallocated without updating other pointers, leading to a potential
use-after-free and exploitable crash.
References
o Bug 1670358
# CVE-2020-15999: Heap buffer overflow in freetype
Reporter
Sergei Glazunov of Google Project Zero
Impact
moderate
Description
In Freetype, if PNG images were embedded into fonts, the Load_SBit_Png function
contained an integer overflow that led to a heap buffer overflow, memory
corruption, and an exploitable crash.
Note: While Project Zero did discover instances of this vulnerability being
exploited in the wild against Chrome, in Firefox this vulnerability is only
triggerable if a rarely-used, hidden preference is toggled, and only affected
Linux and Android operating systems. Other operating systems are unaffected;
and Linux and Android are unaffected in the default configuration.
References
o Bug 1672223
# CVE-2020-26961: DoH did not filter IPv4 mapped IP Addresses
Reporter
Gabriel Corona
Impact
moderate
Description
When DNS over HTTPS is in use, it intentionally filters RFC1918 and related IP
ranges from the responses as these do not make sense coming from a DoH
resolver. However when an IPv4 address was mapped through IPv6, these addresses
were erroneously let through, leading to a potential DNS Rebinding attack.
References
o Bug 1672528
# CVE-2020-26962: Cross-origin iframes supported login autofill
Reporter
Paul Stone
Impact
low
Description
Cross-origin iframes that contained a login form could have been recognized by
the login autofill service, and populated. This could have been used in
clickjacking attacks, as well as be read across partitions in dynamic first
party isolation.
References
o Bug 610997
# CVE-2020-26963: History and Location interfaces could have been used to hang
the browser
Reporter
Sachin Raste
Impact
low
Description
Repeated calls to the history and location interfaces could have been used to
hang the browser. This was addressed by introducing rate-limiting to these API
calls.
References
o Bug 1314912
# CVE-2020-26964: Firefox for Android's Remote Debugging via USB could have
been abused by untrusted apps on older versions of Android
Reporter
Muneaki Nishimura
Impact
low
Description
If the Remote Debugging via USB feature was enabled in Firefox for Android on
an Android version prior to Android 6.0, untrusted apps could have connected to
the feature and operated with the privileges of the browser to read and
interact with web content. The feature was implemented as a unix domain socket,
protected by the Android SELinux policy; however, SELinux was not enforced for
versions prior to 6.0. This was fixed by removing the Remote Debugging via USB
feature from affected devices.
Note: This issue only affected Firefox for Android. Other operating systems are
unaffected.
References
o Bug 1658865
# CVE-2020-26965: Software keyboards may have remembered typed passwords
Reporter
Makoto Kato
Impact
low
Description
Some websites have a feature "Show Password" where clicking a button will
change a password field into a textbook field, revealing the typed password.
If, when using a software keyboard that remembers user input, a user typed
their password and used that feature, the type of the password field was
changed, resulting in a keyboard layout change and the possibility for the
software keyboard to remember the typed password.
References
o Bug 1661617
# CVE-2020-26966: Single-word search queries were also broadcast to local
network
Reporter
tiebuchen
Impact
low
Description
Searching for a single word from the address bar caused an mDNS request to be
sent on the local network searching for a hostname consisting of that string;
resulting in an information leak.
Note: This issue only affected Windows operating systems. Other operating
systems are unaffected.
References
o Bug 1663571
# CVE-2020-26967: Mutation Observers could break or confuse Firefox Screenshots
feature
Reporter
Kaizer Soze
Impact
low
Description
When listening for page changes with a Mutation Observer, a malicious web page
could confuse Firefox Screenshots into interacting with elements other than
those that it injected into the page. This would lead to internal errors and
unexpected behavior in the Screenshots code.
References
o Bug 1665820
# CVE-2020-26968: Memory safety bugs fixed in Firefox 83 and Firefox ESR 78.5
Reporter
Mozilla developers and community
Impact
high
Description
Mozilla developers Randell Jesup, Christian Holler, Jason Kratzer, Byron
Campen, and Steve Fink reported memory safety bugs present in Firefox 82 and
Firefox ESR 78.4. 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 83 and Firefox ESR 78.5
# CVE-2020-26969: Memory safety bugs fixed in Firefox 83
Reporter
Mozilla developers and community
Impact
high
Description
Mozilla developers Tyson Smith, Aaron Klotz, David Major and Jason Kratzer
reported memory safety bugs present in Firefox 82. 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 83
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