Mozilla Firefox 27, released on Tuesday, includes 13 patches, four of which address critical vulnerabilities.
Of the critical flaws, one involves a crash when using web workers with asm.js, one involves use-after-free with imgRequestProxy and image processing, another involves incorrect use of discarded images by RasterImage, and the final one involves miscellaneous memory safety hazards, according to a security advisory.
Mozilla defines critical flaws as vulnerabilities that can be used to run attacker code and install software, requiring no interaction by users other than regular browsing.
“In general this flaw cannot be exploited through email in the Thunderbird and Seamonkey products because scripting is disabled in mail, but is potentially a risk in browser or browser-like contexts,” according to a note posted in the description for each of the four critical vulnerabilities.
In an email correspondence, Wolfgang Kandek, CTO of Qualys, told SCMagazine.com that the attacks deemed critical could allow an attacker to take over a targeted computer.
“Attacks of this type usually come through a website that the attacker controls, either itself a victim of the attacker that counts on the site's normal visitors to fall prey to the attack, or specifically setup for the task and then using ‘Search Engine Poisoning' to attract visitors to the site,” Kandek said.