An issue was discovered in Squid through 4.7. When handling the tag esi:when when ESI is enabled, Squid calls ESIExpression::Evaluate. This function uses a fixed stack buffer to hold the expression while it's being evaluated. When processing the expression, it could either evaluate the top of the stack, or add a new member to the stack. When adding a new member, there is no check to ensure that the stack won't overflow.
{
"availability": "No subscription required",
"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-common",
"binary_version": "3.5.12-1ubuntu7.11"
},
{
"binary_name": "squid-purge",
"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"
}
]
}
{
"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-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-common",
"binary_version": "4.10-1ubuntu1.1"
},
{
"binary_name": "squid-purge",
"binary_version": "4.10-1ubuntu1.1"
},
{
"binary_name": "squidclient",
"binary_version": "4.10-1ubuntu1.1"
}
]
}