Apple has issued a second security update to its web browser Safari in as many weeks.

Unlike the November 13 update, which added anti-phishing protection and patched 11 security vulnerabilities - more than two-thirds of them critical - version 3.2.1 fixes unspecified 'stability improvements', according to a terse notice on the Apple website.

Although the notice included a link to the 'Apple security update' page - where the company normally provides pointers to security advisories associated with such updates - there was no listing there for Safari 3.2.1.

"It would be too much of an understatement to say 'more of the same'," said Andrew Storms, director of security operations at nCircle Network Security

"But in doing so, it also represents the lethargic approach we've come to expect with Apple updates. If only they would put some of that creative spirit we love about Apple into their security development lifecycle."

Although Apple's scant information about Safari 3.2.1 made it impossible to know for certain, some people speculated on the company's support forum that the update was aimed at fixing problems users reported with Safari 3.2 since its release. Among the complaints: frequent crashes, particularly when the new anti-phishing feature was enabled.

One thread on the Safari support forum titled 'Safari 3.2 is Unusable - Spontaneously Quits' has collected more than 100 messages and been viewed nearly 4,000 times since it was opened on November 13.

However, the update doesn't appear to have stopped browser crashes. One user, at least, said it had not. "[Safari] 3.2.1 still crashed for me," said a user identified as Raymond Smith.

Apple updated both the Mac OS X and Windows versions of Safari to 3.2.1. Mac OS X users can download and install 3.2.1 using Safari's built-in update feature, or on Windows, by running the separate Apple Software Update utility.