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.
lists.opensuse.org/opensuse-security-announce/2020-05/msg00018.html
www.openwall.com/lists/oss-security/2020/04/23/1
gitlab.com/jeriko.one/security/-/blob/master/squid/CVEs/CVE-2019-12519.txt
lists.debian.org/debian-lts-announce/2020/07/msg00009.html
security.gentoo.org/glsa/202005-05
security.netapp.com/advisory/ntap-20210205-0006/
usn.ubuntu.com/4356-1/
www.debian.org/security/2020/dsa-4682