The remote host is missing an update to aria2 announced via advisory DSA 1957-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%201957-1

It was discovered that aria2, a high speed download utility, is prone to a buffer overflow in the DHT routing code, which might lead to the execution of arbitrary code. For the stable distribution (lenny), this problem has been fixed in version 0.14.0-1+lenny1. Binaries for powerpc, arm, ia64 and hppa will be provided once they are available. The oldstable distribution (etch) is not affected by this problem. For the testing distribution (squeeze) and the unstable distribution (sid), this problem has been fixed in version 1.2.0-1. We recommend that you upgrade your aria2 packages.