Ubuntu: USN-3477-3: Firefox regressions

Description

USN-3477-1 fixed vulnerabilities in Firefox. The update introduced various minor regressions. This update fixes the problems.

We apologize for the inconvenience.

Original advisory details:

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, read uninitialized memory, obtain sensitive information, bypass same-origin restrictions, bypass CSP protections, bypass mixed content blocking, spoof the addressbar, or execute arbitrary code. (CVE-2017-7826,CVE-2017-7827, CVE-2017-7828,CVE-2017-7830,CVE-2017-7831,CVE-2017-7832,CVE-2017-7833, CVE-2017-7834,CVE-2017-7835,CVE-2017-7837,CVE-2017-7838,CVE-2017-7842) It was discovered that javascript: URLs pasted in to the addressbar would be executed instead of being blocked in some circumstances. If a user were tricked in to copying a specially crafted URL in to the addressbar, an attacker could potentially exploit this to conduct cross-site scripting (XSS) attacks. (CVE-2017-7839) It was discovered that exported bookmarks do not strip script elements from user-supplied tags. If a user were tricked in to adding specially crafted tags to bookmarks, exporting them and then opening the resulting HTML file, an attacker could potentially exploit this to conduct cross-site scripting (XSS) attacks. (CVE-2017-7840)