Mozilla Foundation Security Advisory 2020-05

Security Vulnerabilities fixed in Firefox 73

Announced February 11, 2020 Impact high Products Firefox Fixed in Firefox 73

# CVE-2020-6796: Missing bounds check on shared memory read in the parent process Reporter Thomas Imbert Impact high Description 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. References Bug 1610426

# CVE-2020-6797: Extensions granted downloads.open permission could open arbitrary applications on Mac OSX Reporter Vladimir Metnew Impact moderate Description 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 unaffected. References Bug 1596668

# CVE-2020-6798: Incorrect parsing of template tag could result in JavaScript injection Reporter terjanq Impact moderate Description If a <template> tag was used in a <select%gt; tag, the parser could be confused and allow JavaScript parsing and execution when it should not be allowed. A site that relied on the browser behaving correctly could suffer a cross-site scripting vulnerability as a result. References Bug 1602944

# CVE-2020-6799: Arbitrary code execution when opening pdf links from other applications, when Firefox is configured as default pdf reader Reporter Joshua Graham & Brendan Scarvell Impact moderate Description 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. References Bug 1606596

# CVE-2020-6800: Memory safety bugs fixed in Firefox 73 and Firefox ESR 68.5 Reporter Mozilla developers and community Impact high Description 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. References Memory safety bugs fixed in Firefox 73 and Firefox ESR 68.5