Ubuntu Security Notice 1890-2 - USN-1890-1 fixed vulnerabilities in Firefox. This update introduced a regression which sometimes resulted in Firefox using the wrong network proxy settings. This update fixes the problem.
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Ubuntu Security Notice 1890-1 - Multiple memory safety issues were discovered in Firefox. If the user were tricked into opening a specially crafted page, an attacker could possibly exploit these to cause a denial of service via application crash, or potentially execute arbitrary code with the privileges of the user invoking Firefox. Abhishek Arya discovered multiple use-after-free bugs. If the user were tricked into opening a specially crafted page, an attacker could possibly exploit these to execute arbitrary code with the privileges of the user invoking Firefox. Various other issues were also addressed.
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