A buffer overflow has been detected in the X11 dissector of ethereal, a commonly used network traffic analyser. A remote attacker may be able to overflow a buffer using a specially crafted IP packet. More problems have been discovered which don't apply to the version in woody but are fixed in sid as well.
For the stable distribution (woody) this problem has been fixed in version 0.9.4-1woody11.
For the unstable distribution (sid) this problem has been fixed in version 0.10.9-1.
We recommend that you upgrade your ethereal package.