Mozilla has shipped a new version of its Firefox web browser with increased support for HTML5, faster startup times and improved per-site permission management. But most importantly it fixes a number of critical vulnerabilities, some serious enough to expose web surfers to drive-by download attacks.

The Critical and High impact bugs include:

• Mozilla identified and fixed several memory safety bugs in the browser engine used in Firefox 4, Firefox 5 and other Mozilla-based products. Some of these bugs showed evidence of memory corruption under certain circumstances, and we presume that with enough effort at least some of these could be exploited to run arbitrary code.
• Rafael Gieschke reported that unsigned JavaScript could call into script inside a signed JAR thereby inheriting the identity of the site that signed the JAR as well as any permissions that a user had granted the signed JAR.
• Michael Jordon of Context IS reported that an overly long shader program could cause a buffer overrun and crash in a string class used to store the shader source code.
• Michael Jordon of Context IS reported a potentially exploitable heap overflow in the ANGLE library used by Mozilla’s WebGL implementation.
• Security researcher regenrecht reported via TippingPoint’s Zero Day Initiative that a SVG text manipulation routine contained a dangling pointer vulnerability.
• Mike Cardwell reported that Content Security Policy violation reports failed to strip out proxy authorization credentials from the list of request headers. Daniel Veditz reported that redirecting to a website with Content Security Policy resulted in the incorrect resolution of hosts in the constructed policy.
• nasalislarvatus3000 reported that when using Windows D2D hardware acceleration, image data from one domain could be inserted into a canvas and read by a different domain.