An issue was discovered in Squid through 4.7. When Squid is parsing ESI, it keeps the ESI elements in ESIContext. ESIContext contains a buffer for holding a stack of ESIElements. When a new ESIElement is parsed, it is added via addStackElement. addStackElement has a check for the number of elements in this buffer, but it's off by 1, leading to a Heap Overflow of 1 element. The overflow is within the same structure so it can't affect adjacent memory blocks, and thus just leads to a crash while processing.
{ "binaries": [ { "binary_name": "squid", "binary_version": "3.5.12-1ubuntu7.11" }, { "binary_name": "squid-cgi", "binary_version": "3.5.12-1ubuntu7.11" }, { "binary_name": "squid-cgi-dbgsym", "binary_version": "3.5.12-1ubuntu7.11" }, { "binary_name": "squid-common", "binary_version": "3.5.12-1ubuntu7.11" }, { "binary_name": "squid-dbg", "binary_version": "3.5.12-1ubuntu7.11" }, { "binary_name": "squid-dbgsym", "binary_version": "3.5.12-1ubuntu7.11" }, { "binary_name": "squid-purge", "binary_version": "3.5.12-1ubuntu7.11" }, { "binary_name": "squid-purge-dbgsym", "binary_version": "3.5.12-1ubuntu7.11" }, { "binary_name": "squid3", "binary_version": "3.5.12-1ubuntu7.11" }, { "binary_name": "squidclient", "binary_version": "3.5.12-1ubuntu7.11" }, { "binary_name": "squidclient-dbgsym", "binary_version": "3.5.12-1ubuntu7.11" } ], "availability": "No subscription required" }
{ "binaries": [ { "binary_name": "squid", "binary_version": "3.5.27-1ubuntu1.6" }, { "binary_name": "squid-cgi", "binary_version": "3.5.27-1ubuntu1.6" }, { "binary_name": "squid-common", "binary_version": "3.5.27-1ubuntu1.6" }, { "binary_name": "squid-dbg", "binary_version": "3.5.27-1ubuntu1.6" }, { "binary_name": "squid-purge", "binary_version": "3.5.27-1ubuntu1.6" }, { "binary_name": "squid3", "binary_version": "3.5.27-1ubuntu1.6" }, { "binary_name": "squidclient", "binary_version": "3.5.27-1ubuntu1.6" } ], "availability": "No subscription required" }
{ "binaries": [ { "binary_name": "squid", "binary_version": "4.10-1ubuntu1.1" }, { "binary_name": "squid-cgi", "binary_version": "4.10-1ubuntu1.1" }, { "binary_name": "squid-cgi-dbgsym", "binary_version": "4.10-1ubuntu1.1" }, { "binary_name": "squid-common", "binary_version": "4.10-1ubuntu1.1" }, { "binary_name": "squid-dbgsym", "binary_version": "4.10-1ubuntu1.1" }, { "binary_name": "squid-purge", "binary_version": "4.10-1ubuntu1.1" }, { "binary_name": "squid-purge-dbgsym", "binary_version": "4.10-1ubuntu1.1" }, { "binary_name": "squidclient", "binary_version": "4.10-1ubuntu1.1" }, { "binary_name": "squidclient-dbgsym", "binary_version": "4.10-1ubuntu1.1" } ], "availability": "No subscription required" }