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Mozilla Patches 13 Vulnerabilities With Release of Firefox 38

Firefox 38 was made available for download on Tuesday. Mozilla has addressed a total of 13 vulnerabilities in the latest version of its web browser, including five critical security bugs.

One of the critical flaws is a buffer overflow triggered while parsing compressed XML content (CVE-2015-2716). The vulnerability, discovered by Ucha Gobejishvili, is caused by an error in how buffer space is created and modified when handling large amounts of XML data. The bug leads to a potentially exploitable crash, Mozilla said.

Another critical vulnerability fixed in Firefox 38 is a use-after-free during the processing of text when vertical text is enabled (CVE-2015-2713). The issue, discovered by Scott Bell, also leads to a potentially exploitable crash.

Dougall Johnson reported an incorrect asm.js bounds check elimination vulnerability (CVE-2015-2712).

“Security researcher Dougall Johnson reported an out-of-bounds read and write in asm.js during JavaScript validation due to an error in how heap lengths are defined. This results in a potentially exploitable crash and could allow for the reading of random memory which may contain sensitive data,” Mozilla said in its advisory.

Finland-based bug bounty hunter Atte Kettunen, who has identified numerous bugs in Google Chrome, reported a critical heap-based buffer overflow vulnerability triggered during the rendering of SVG format graphics when combined with specific CSS properties on a page (CVE-2015-2710).

Several memory safety bugs in the browser engine, identified by the Mozilla community and developers, have also been rated critical.

Firefox 38 patches a total of five high severity vulnerabilities, including a buffer overflow during video playback on Linux systems, a buffer overflow and out-of-bounds read in the libstagefright library while parsing invalid metadata in MP4 video files, a bug in how WebChannel.jsm handles message traffic, and a privilege escalation through Inter-process Communication (IPC) channel messages. The latest version of the web browser also includes a comprehensive fix for a vulnerability initially addressed in Firefox 36.

Some of these vulnerabilities also affect Firefox ESR, and the Thunderbird email client.

With the release of Firefox 38, Mozilla also announced integration with the Adobe Content Decryption Module (CDM) for playing DRM-wrapped content within the HTML5 video tag.

“We don’t believe DRM is a desirable market solution, but it’s currently the only way to watch a sought-after segment of content,” explained Denelle Dixon-Thayer, senior vice president of business and legal affairs at Mozilla Corporation.

In an effort to provide a layer of security, Mozilla has decided to develop a security sandbox that sits around the CDM. The company has noted that the CDM can be removed from Firefox, or users can install a version of the web browser that doesn’t have the CDM enabled by default.

Related: Mozilla Disables Opportunistic Encryption in Firefox After Security Flaw Discovered

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Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.