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AUSCERT External Security Bulletin Redistribution
ESB-2020.3612
MFSA 2020-45 & MFSA 2020-46: Security Vulnerabilities fixed
in Firefox & Firefox ESR
21 October 2020
===========================================================================
AusCERT Security Bulletin Summary
---------------------------------
Product: Mozilla Firefox
Mozilla Firefox ESR
Publisher: Mozilla
Operating System: Windows
UNIX variants (UNIX, Linux, OSX)
Impact/Access: Execute Arbitrary Code/Commands -- Remote with User Interaction
Denial of Service -- Remote with User Interaction
Provide Misleading Information -- Remote with User Interaction
Reduced Security -- Remote with User Interaction
Resolution: Patch/Upgrade
CVE Names: CVE-2020-15969 CVE-2020-15684 CVE-2020-15683
CVE-2020-15682 CVE-2020-15681 CVE-2020-15680
CVE-2020-15254
Reference: ESB-2020.3531
Original Bulletin:
https://www.mozilla.org/en-US/security/advisories/mfsa2020-45/
https://www.mozilla.org/en-US/security/advisories/mfsa2020-46/
Comment: This bulletin contains two (2) Mozilla security advisories.
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Mozilla Foundation Security Advisory 2020-45
Security Vulnerabilities fixed in Firefox 82
Announced
October 20, 2020
Impact
high
Products
Firefox
Fixed in
Firefox 82
# CVE-2020-15969: Use-after-free in usersctp
Reporter
Mark Wodrich of Google
Impact
high
Description
A use-after-free bug in the usersctp library was reported upstream. We assume
this could have led to memory corruption and a potentially exploitable crash.
References
o Bug 1666570
o [sctplab] upstream usrsctp fix
# CVE-2020-15254: Undefined behavior in bounded channel of crossbeam rust crate
Reporter
Caelum van Ispelen
Impact
high
Description
In the crossbeam rust crate, the bounded channel incorrectly assumed that
Vec::from_iter had allocated capacity that was the same as the number of
iterator elements. Vec::from_iter does not actually guarantee that and may
allocate extra memory. The destructor of the bounded channel reconstructs Vec
from the raw pointer based on the incorrect assumptions - this is unsound and
caused a deallocation with the incorrect capacity when Vec::from_iter had
allocated different sizes than the number of iterator elements. The impact on
Firefox is undetermined, but in another use case, the behavior was causing
corruption of jemalloc structures.
References
o Bug 1668514
o [crossbeam-rs] Undefined Behavior in bounded channel
# CVE-2020-15680: Presence of external protocol handlers could be determined
through image tags
Reporter
Rotem Kerner
Impact
moderate
Description
If a valid external protocol handler was referenced in an image tag, the
resulting broken image size could be distinguished from a broken image size of
a non-existent protocol handler. This allowed an attacker to successfully probe
whether an external protocol handler was registered.
References
o Bug 1658881
# CVE-2020-15681: Multiple WASM threads may have overwritten each others' stub
table entries
Reporter
Alon Zakai
Impact
moderate
Description
When multiple WASM threads had a reference to a module, and were looking up
exported functions, one WASM thread could have overwritten another's entry in a
shared stub table, resulting in a potentially exploitable crash.
References
o Bug 1666568
# CVE-2020-15682: The domain associated with the prompt to open an external
protocol could be spoofed to display the incorrect origin
Reporter
Lijo A.T.
Impact
low
Description
When a link to an external protocol was clicked, a prompt was presented that
allowed the user to choose what application to open it in. An attacker could
induce that prompt to be associated with an origin they didn't control,
resulting in a spoofing attack. This was fixed by changing external protocol
prompts to be tab-modal while also ensuring they could not be incorrectly
associated with a different origin.
References
o Bug 1636654
# CVE-2020-15683: Memory safety bugs fixed in Firefox 82 and Firefox ESR 78.4
Reporter
Mozilla developers and community
Impact
high
Description
Mozilla developers and community members Simon Giesecke, Christian Holler,
Philipp, and Jason Kratzer reported memory safety bugs present in Firefox 81
and Firefox ESR 78.3. 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 82 and Firefox ESR 78.4
# CVE-2020-15684: Memory safety bugs fixed in Firefox 82
Reporter
Mozilla developers
Impact
high
Description
Mozilla developers Christian Holler, Sebastian Hengst, Bogdan Tara, and Tyson
Smith reported memory safety bugs present in Firefox 81. 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 82
- --------------------------------------------------------------------------------
Mozilla Foundation Security Advisory 2020-46
Security Vulnerabilities fixed in Firefox ESR 78.4
Announced
October 20, 2020
Impact
high
Products
Firefox ESR
Fixed in
Firefox ESR 78.4
# CVE-2020-15969: Use-after-free in usersctp
Reporter
Mark Wodrich of Google
Impact
high
Description
A use-after-free bug in the usersctp library was reported upstream. We assume
this could have led to memory corruption and a potentially exploitable crash.
References
o Bug 1666570
o [sctplab] upstream usrsctp fix
# CVE-2020-15683: Memory safety bugs fixed in Firefox 82 and Firefox ESR 78.4
Reporter
Mozilla developers and community
Impact
high
Description
Mozilla developers and community members Jason Kratzer, Simon Giesecke,
Philipp, and Christian Holler reported memory safety bugs present in Firefox 81
and Firefox ESR 78.3. 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 82 and Firefox ESR 78.4
- --------------------------END INCLUDED TEXT--------------------
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