Matthew Daley discovered that Squid3, a fully featured web proxy cache, did not properly perform input validation in request parsing. A remote attacker could use this flaw to mount a denial of service by sending crafted Range requests.
For the stable distribution (wheezy), this problem has been fixed in version 3.1.20-2.2+deb7u2.
For the unstable distribution (sid), this problem will be fixed soon.
We recommend that you upgrade your squid3 packages.