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.
{
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{
"binary_version": "3.5.12-1ubuntu7.11",
"binary_name": "squidclient"
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"availability": "No subscription required"
}
{
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"binary_version": "3.5.27-1ubuntu1.6",
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{
"binary_version": "3.5.27-1ubuntu1.6",
"binary_name": "squidclient"
}
],
"availability": "No subscription required"
}
{
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{
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"binary_version": "4.10-1ubuntu1.1",
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{
"binary_version": "4.10-1ubuntu1.1",
"binary_name": "squidclient"
}
],
"availability": "No subscription required"
}