{"id":"ALPINE-CVE-2019-12521","details":"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.","modified":"2026-09-09T06:17:50.054950556Z","published":"2020-04-15T19:15:12.393Z","upstream":["CVE-2019-12521"],"references":[{"type":"ADVISORY","url":"https://security.alpinelinux.org/vuln/CVE-2019-12521"}],"affected":[{"package":{"name":"squid","ecosystem":"Alpine:v3.10","purl":"pkg:apk/alpine/squid?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.0"},{"fixed":"4.11-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/alpine/ALPINE-CVE-2019-12521.json"}},{"package":{"name":"squid","ecosystem":"Alpine:v3.11","purl":"pkg:apk/alpine/squid?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.0"},{"fixed":"4.11-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/alpine/ALPINE-CVE-2019-12521.json"}},{"package":{"name":"squid","ecosystem":"Alpine:v3.9","purl":"pkg:apk/alpine/squid?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.0"},{"fixed":"4.11-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/alpine/ALPINE-CVE-2019-12521.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}