Oracle released an emergency update to its Java software for surfing the Web on Sunday but questions remain on whether the updated software is safe.

The Security Alert CVE-2012-042 released by Oracle on Sunday addresses two vulnerabilities affecting Java in web browsers, according to Oracle.

These vulnerabilities do not affect Java on servers, Java desktop applications, or embedded Java.

They are both remotely exploitable without authentication. Oracle recommends that this Security Alert be applied as soon as possible because these issues may be exploited "in the wild" and some exploits are available in various hacking tools.

The exploit conditions for these vulnerabilities are the same. To be successfully exploited, an attacker needs to trick an unsuspecting user into browsing a malicious website. The execution of the malicious applet within the browser of the unsuspecting users then allows the attacker to execute arbitrary code in the vulnerable system. These vulnerabilities are applicable only to Java in web browsers because they are exploitable through malicious browser applets.

With this Security Alert, Oracle is also switching Java security settings to "high" by default. The high security setting requires users to expressly authorize the execution of applets which are either unsigned or are self-signed. As a result, unsuspecting users visiting malicious web sites will be notified before an applet is run and will gain the ability to deny the execution of the potentially malicious applet.

Oracle released the update just days after the U.S. Department of Homeland Security urged PC users to disable the program because of bugs in the software that were being exploited to commit identity theft and other crimes.

Adam Gowdiak, a researcher with Poland's Security Explorations who has discovered several bugs in the software over the past year, said that the update from Oracle leaves unfixed several critical security flaws.

"We don't dare to tell users that it's safe to enable Java again," said Gowdiak.

Responding to Oracle's updated software, the U.S. Department of Homeland Security reiterated advice for computer users to disable Java software for surfing the Web.

"Unless it is absolutely necessary to run Java in web browsers, disable it," the Department of Homeland Security's Computer Emergency Readiness Team said on Monday in a posting on its website.