The arrayShrink function (lib/Array.c) in Squid 2.6.STABLE17 allows attackers to cause a denial of service (process exit) via unknown vectors that cause an array to shrink to 0 entries, which triggers an assert error. NOTE: this issue is due to an incorrect fix for CVE-2007-6239.
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.