From Secunia:
Description:
Multiple vulnerabilities have been reported in Apple QuickTime, which can be exploited by malicious people to compromise a user's system.
1) Errors in the processing of H.264 movies can be exploited to trigger an integer overflow or buffer overflow.
2) A boundary error within the processing of QuickTime movies can be exploited to cause a buffer overflow.
3) A boundary error within the processing of FLC movies can be exploited to cause a heap-based buffer overflow via a FLC movie with a specially crafted COLOR_64 chunk.
4) Errors within the processing of FlashPix files can be exploited to cause an integer overflow or buffer overflow.
5) An error within the processing of FlashPix files can be exploited to trigger an exception leaving an uninitialised object.
6) A boundary error within the processing of SGI images can be exploited to cause a buffer overflow.
Successful exploitation of the vulnerabilities may allow execution of arbitrary code.
Solution:
Update to version 7.1.3.
http://www.apple.com/quicktime/download/