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AUSCERT Security Bulletin
Mozilla Foundation Security Advisory 2020-05
13 February 2020
AusCERT Security Bulletin Summary
Product: Mozilla Firefox
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
CVE Names: CVE-2020-6801 CVE-2020-6800 CVE-2020-6799
CVE-2020-6798 CVE-2020-6797 CVE-2020-6796
Member content until: Friday, March 13 2020
Vulnerabilities have been fixed in Mozilla Firefox 73 
Mozilla has given the following information regarding these vulnerabilities:
February 11, 2020
# CVE-2020-6796: Missing bounds check on shared memory read in the parent
A content process could have modified shared memory relating to crash reporting
information, crash itself, and cause an out-of-bound write. This could have
caused memory corruption and a potentially exploitable crash.
o Bug 1610426
# CVE-2020-6797: Extensions granted downloads.open permission could open
arbitrary applications on Mac OSX
By downloading a file with the .fileloc extension, a semi-privileged extension
could launch an arbitrary application on the user's computer. The attacker is
restricted as they are unable to download non-quarantined files or supply
command line arguments to the application, limiting the impact.
Note: this issue only occurs on Mac OSX. Other operating systems are
o Bug 1596668
If a <template> tag was used in a <select%gt; tag, the parser could be confused
site that relied on the browser behaving correctly could suffer a cross-site
scripting vulnerability as a result.
o Bug 1602944
# CVE-2020-6799: Arbitrary code execution when opening pdf links from other
applications, when Firefox is configured as default pdf reader
Joshua Graham & Brendan Scarvell
Command line arguments could have been injected during Firefox invocation as a
shell handler for certain unsupported file types. This required Firefox to be
configured as the default handler for a given file type and for a file
downloaded to be opened in a third party application that insufficiently
sanitized URL data. In that situation, clicking a link in the third party
application could have been used to retrieve and execute files whose location
was supplied through command line arguments.
Note: This issue only affects Windows operating systems and when Firefox is
configured as the default handler for non-default filetypes. Other operating
systems are unaffected.
o Bug 1606596
# CVE-2020-6800: Memory safety bugs fixed in Firefox 73 and Firefox ESR 68.5
Mozilla developers and community
Mozilla developers and community members Raul Gurzau, Tyson Smith, Bob Clary,
Liz Henry, and Christian Holler reported memory safety bugs present in Firefox
72 and Firefox ESR 68.4. 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.
o Memory safety bugs fixed in Firefox 73 and Firefox ESR 68.5
# CVE-2020-6801: Memory safety bugs fixed in Firefox 73
Mozilla developers Jason Kratzer, Tyson Smith, and Christian Holler reported
memory safety bugs present in Firefox 72. 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.
o Memory safety bugs fixed in Firefox 73" 
It is recommended to upgrade Firefox to the latest version.
 Mozilla Foundation Security Advisory 2020-05
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