Several memory safety bugs were discovered in Mozilla Firefox and Thunderbird. Memory corruption and arbitrary code execution are possible with these vulnerabilities. These bugs can be exploited over the network.A flaw was discovered in both Firefox and Thunderbird where 4 bytes of a HMAC output could be written past the end of a buffer stored on the memory stack. This could allow an attacker to execute arbitrary code or lead to a crash. This flaw can be exploited over the network.A flaw was found in Mozilla Firefox and Thunderbird where null bytes were incorrectly parsed in HTML entities. This could lead to HTML comments being treated as code which could lead to XSS in a web application or HTML entities being masked from filters.A vulnerability was found in Mozilla Firefox and Thunderbird. Privileged JSONView objects that have been cloned into content can be accessed using a form with a data URI. This flaw bypasses existing defense-in-depth mechanisms and can be exploited over the network.A flaw was discovered in Mozilla Firefox and Thunderbird where a fixed-stack buffer overflow could occur during WebRTC signalling. The vulnerability could lead to an exploitable crash or leak data.A use-after-free flaw was found in Mozilla Firefox and Thunderbird. When following a value"s prototype chain, it was possible to retain a reference to a locale, delete it, and subsequently reference it. An attacker could use this flaw to execute code that was stored in the referenced memory or crash the system.In libexpat before 2.2.8, crafted XML input could fool the parser into changing from DTD parsing to document parsing too early; a consecutive call to XML_GetCurrentLineNumber then resulted in a heap-based buffer over-read.A flaw was found in Mozilla"s firefox and thunderbird where if two same-origin documents set document.domain differently to become cross-origin, it was possible for them to call arbitrary DOM methods/getters/setters on the now-cross-origin window. This could cause an interaction between two different sites on two different windows running under the same application.A flaw was found in the 360 Total Security code in Firefox and Thunderbird. Memory corruption is possible in the accessibility engine that could lead to an exploit to run arbitrary code. This vulnerability could be exploited over a network connection and would affect confidentiality and integrity of information as well as availability of the system.