A weakness and multiple vulnerabilities have been reported in Apple iOS, which can be exploited by malicious people with physical access to bypass certain security restrictions and by malicious people to disclose sensitive information, conduct cross-site scripting attacks, bypass certain security restrictions, and compromise a user's device.

1) An error within the CFNetwork component when handling URLs can be exploited to disclose sensitive information by tricking the user into visiting a malicious website.

2) An integer underflow error within the HFS component when handling HFS catalog files can be exploited by mounting a maliciously crafted disk image.

3) A logic error within the kernel does not properly handle debug system calls and can be exploited to bypass the sandbox restrictions.

4) An integer overflow error within the libresolv library when handling DNS resource records can be exploited to corrupt heap memory.

For more information see vulnerability #21 in:
SA47843

5) A race condition error in the Passcode Lock component when handling slide to dial gestures can be exploited to bypass the Passcode Lock screen.

6) The weakness is caused due to the Private Browsing mode in Safari not properly preventing recording of visits to certain sites using the pushState or replaceState JavaScript methods.

7) An error within the Siri component when handling voice commands can be exploited to bypass the screen lock and forward an open mail message to an arbitrary recipient.

8) A format string error in the VPN component when handling racoon configuration files can be exploited to execute arbitrary code via a specially crafted racoon configuration file.

9) A cross-origin error in the WebKit component can be exploited to bypass the same-origin policy and disclose a cookie by tricking the user into visiting a malicious website.

10) An error within the WebKit component when handling drag-and-drop actions can be exploited to conduct cross-site scripting attacks.

11) Multiple unspecified errors within the WebKit component can be exploited to conduct cross-site scripting attacks.

12) Some vulnerabilities are caused due to a bundled vulnerable version of WebKit.

For more information:
SA45698
SA46049
SA46308
SA46594
SA46815
SA47231
SA47694

Successful exploitation of vulnerabilities #2, #4, #8, and #12 may allow execution of arbitrary code.

Solution
Apply iOS 5.1 Software Update.

Provided and/or discovered by
The vendor credits:
1) Erling Ellingsen, Facebook.
2, 8) pod2g.
3) 2012 iOS Jailbreak Dream Team.
5) Roland Kohler, the German Federal Ministry of Economics and Technology.
6) Eric Melville, American Express.
9) Sergey Glazunov.
10) Adam Barth, Google Chrome Security Team.
11) Sergey Glazunov, Jochen Eisinger of Google Chrome Team, Alan Austin of polyvore.com.

Original Advisory
Apple:
http://support.apple.com/kb/HT5192

Other references
Further details available to Secunia VIM customers

Deep Links
Links available to Secunia VIM customers