Affected: Mozilla Thunderbird, Mozilla Firefox ESR, Mozilla Firefox

A use-after-free vulnerability can occur when the SMIL animation controller incorrectly registers with the refresh driver twice when only a single registration is expected. When a registration is later freed with the removal of the animation controller element, the refresh driver incorrectly leaves a dangling pointer to the driver's observer array. This vulnerability affects Thunderbird < 60.6, Firefox ESR < 60.6, and Firefox < 66.

Affected: Ubuntu:16.04:LTS: firefox, Ubuntu:18.04:LTS: firefox

Multiple security issues were discovered in Firefox. If a user were tricked in to opening a specially crafted website, an attacker could potentially exploit these to cause a denial of service via application crash, denial of service via successive FTP authorization prompts or modal alerts, trick the user with confusing permission request prompts, obtain sensitive information, conduct social engineering attacks, or execute arbitrary code. (CVE-2019-9788, CVE-2019-9789, CVE-2019-9790, CVE-2019-9791, CVE-2019-9792, CVE-2019-9795, CVE-2019-9796, CVE-2019-9797, CVE-2019-9799, CVE-2019-9802, CVE-2019-9805, CVE-2019-9806, CVE-2019-9807, CVE-2019-9808, CVE-2019-9809)

A mechanism was discovered that removes some bounds checking for string, array, or typed array accesses if Spectre mitigations have been disabled. If a user were tricked in to opening a specially crafted website with Spectre mitigations disabled, an attacker could potentially exploit this to cause a denial of service, or execute arbitrary code. (CVE-2019-9793)

It was discovered that Upgrade-Insecure-Requests was incorrectly enforced for same-origin navigation. An attacker could potentially exploit this to conduct machine-in-the-middle (MITM) attacks. (CVE-2019-9803)