USN-3260-1 caused a regression in Firefox.
USN-3260-1 fixed vulnerabilities in Firefox. The update caused the date picker panel and form validation errors to close immediately on opening. This update fixes the problem.
11 May 2017
A security issue affects these releases of Ubuntu and its derivatives:
USN-3260-1 caused a regression in Firefox.
USN-3260-1 fixed vulnerabilities in Firefox. The update caused the date picker panel and form validation errors to close immediately on opening. This update fixes the problem.
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 read uninitialized memory, obtain sensitive information, spoof the addressbar contents or other UI elements, escape the sandbox to read local files, conduct cross-site scripting (XSS) attacks, cause a denial of service via application crash, or execute arbitrary code. (CVE-2017-5429, CVE-2017-5430, CVE-2017-5432, CVE-2017-5433, CVE-2017-5434, CVE-2017-5435, CVE-2017-5436, CVE-2017-5437, CVE-2017-5438, CVE-2017-5439, CVE-2017-5440, CVE-2017-5441, CVE-2017-5442, CVE-2017-5443, CVE-2017-5444, CVE-2017-5445, CVE-2017-5446, CVE-2017-5447, CVE-2017-5448, CVE-2017-5449, CVE-2017-5451, CVE-2017-5453, CVE-2017-5454, CVE-2017-5455, CVE-2017-5456, CVE-2017-5458, CVE-2017-5459, CVE-2017-5460, CVE-2017-5461, CVE-2017-5464, CVE-2017-5465, CVE-2017-5466, CVE-2017-5467, CVE-2017-5468, CVE-2017-5469)
A flaw was discovered in the DRBG number generation in NSS. If an attacker were able to perform a man-in-the-middle attack, this flaw could potentially be exploited to view sensitive information. (CVE-2017-5462)
The problem can be corrected by updating your system to the following package versions:
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
After a standard system update you need to restart Firefox to make all the necessary changes.