Yesterday Skype published an security advisory about heap overflow in Skype user client. According to another advisory published by EADS/CRC this vulnerability is remotely exploitable, and is not affected by heap protection used in Windows XP or Linux.
So updating your Skype client is a really good idea.
Vulnerability details from Skype Advisory:
Bulletin title: Heap overflow in networking routine Bulletin ID: SKYPE-SB/2005-003 CVE references: CVE-2005-3267 Risk assessment: HIGH
The following Skype clients are vulnerable to this attack:
Skype for Windows: All releases prior to and including 1.4.*.83
Skype for Mac OS X: All releases prior to and including 1.3.*.16
Skype for Linux: All releases prior to and including 1.2.*.17
Skype for Pocket PC: All releases prior to and including 1.1.*.6
Fixed versions:
Skype for Windows: Release 1.4.*.84 or later
Skype for Mac OS X: Release 1.3.*.17 or later
Skype for Linux: Release 1.2.*.18 or later
Skype for Pocket PC: No patch is yet available. This bulletin will be updated when it has been made available.