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.
Image SLES15-SP1-Manager-4-0-Azure-BYOS-Proxy Image SLES15-SP1-Manager-4-0-EC2-HVM-BYOS-Proxy Image SLES15-SP1-Manager-4-0-GCE-BYOS-Proxy Image SLES15-SP2-Manager-4-1-Proxy-BYOS-Azure Image SLES15-SP2-Manager-4-1-Proxy-BYOS-EC2-HVM Image SLES15-SP2-Manager-4-1-Proxy-BYOS-GCE Image SLES15-SP3-Manager-4-2-Proxy-BYOS-Azure Image SLES15-SP3-Manager-4-2-Proxy-BYOS-EC2-HVM Image SLES15-SP3-Manager-4-2-Proxy-BYOS-GCE openSUSE Leap 15.1 openSUSE Tumbleweed SUSE CaaS Platform 4.0 SUSE Linux Enterprise High Performance Computing 15 SP1 SUSE Linux Enterprise High Performance Computing 15 SP2 SUSE Linux Enterprise High Performance Computing 15 SP3 SUSE Linux Enterprise High Performance Computing 15 SP4 SUSE Linux Enterprise High Performance Computing 15-ESPOS SUSE Linux Enterprise High Performance Computing 15-LTSS SUSE Linux Enterprise Module for Server Applications 15 SP1 SUSE Linux Enterprise Module for Server Applications 15 SP2 SUSE Linux Enterprise Module for Server Applications 15 SP3 SUSE Linux Enterprise Module for Server Applications 15 SP4 SUSE Linux Enterprise Point of Sale 11 SP3 SUSE Linux Enterprise Point of Sale 12 SP2-CLIENT SUSE Linux Enterprise Server 11 SP1-TERADATA SUSE Linux Enterprise Server 11 SP3-TERADATA SUSE Linux Enterprise Server 11 SP4-LTSS SUSE Linux Enterprise Server 12 SP2-BCL SUSE Linux Enterprise Server 12 SP2-ESPOS SUSE Linux Enterprise Server 12 SP2-LTSS SUSE Linux Enterprise Server 12 SP3-BCL SUSE Linux Enterprise Server 12 SP3-ESPOS SUSE Linux Enterprise Server 12 SP3-LTSS SUSE Linux Enterprise Server 12 SP3-TERADATA SUSE Linux Enterprise Server 12 SP4 SUSE Linux Enterprise Server 12 SP5 SUSE Linux Enterprise Server 15 SP1 SUSE Linux Enterprise Server 15 SP2 SUSE Linux Enterprise Server 15 SP3 SUSE Linux Enterprise Server 15 SP4 SUSE Linux Enterprise Server 15-LTSS SUSE Linux Enterprise Server for SAP Applications 11 SP1-TERADATA SUSE Linux Enterprise Server for SAP Applications 11 SP3-TERADATA SUSE Linux Enterprise Server for SAP Applications 11 SP4-LTSS SUSE Linux Enterprise Server for SAP Applications 12 SP2 SUSE Linux Enterprise Server for SAP Applications 12 SP2-BCL SUSE Linux Enterprise Server for SAP Applications 12 SP2-ESPOS SUSE Linux Enterprise Server for SAP Applications 12 SP2-LTSS SUSE Linux Enterprise Server for SAP Applications 12 SP3 SUSE Linux Enterprise Server for SAP Applications 12 SP3-BCL SUSE Linux Enterprise Server for SAP Applications 12 SP3-ESPOS SUSE Linux Enterprise Server for SAP Applications 12 SP3-LTSS SUSE Linux Enterprise Server for SAP Applications 12 SP3-TERADATA SUSE Linux Enterprise Server for SAP Applications 12 SP4 SUSE Linux Enterprise Server for SAP Applications 12 SP5 SUSE Linux Enterprise Server for SAP Applications 15 SUSE Linux Enterprise Server for SAP Applications 15 SP1 SUSE Linux Enterprise Server for SAP Applications 15 SP2 SUSE Linux Enterprise Server for SAP Applications 15 SP3 SUSE Linux Enterprise Server for SAP Applications 15 SP4 SUSE Linux Enterprise Storage 6 SUSE Linux Enterprise Storage 7 SUSE Linux Enterprise Storage 7.1 SUSE Manager Proxy 4.0 SUSE Manager Proxy 4.1 SUSE Manager Proxy 4.2 SUSE Manager Proxy 4.3 SUSE Manager Retail Branch Server 4.0 SUSE Manager Retail Branch Server 4.1 SUSE Manager Retail Branch Server 4.2 SUSE Manager Retail Branch Server 4.3 SUSE Manager Server 4.0 SUSE Manager Server 4.1 SUSE Manager Server 4.2 SUSE Manager Server 4.3 SUSE OpenStack Cloud 7 SUSE OpenStack Cloud 8 SUSE OpenStack Cloud Crowbar 8