{"id":"CVE-2019-12523","url":"https://www.cyber-defence.io/tools/cve/CVE-2019-12523","generatedAt":"2026-10-28T21:31:56.824Z","title":"This causes all access checks to be bypassed and allows access to restricted HTTP servers, e.g., an attacker can connect to HTTP servers that only listen on localhost.","description":"An issue was discovered in Squid before 4.9. When handling a URN request, a corresponding HTTP request is made. This HTTP request doesn't go through the access checks that incoming HTTP requests go through. This causes all access checks to be bypassed and allows access to restricted HTTP servers, e.g., an attacker can connect to HTTP servers that only listen on localhost.","published":"2019-11-26T17:15:11.000Z","lastModified":"2026-06-17T02:14:49.000Z","status":"Modified","sourceIdentifier":"cve@mitre.org","cvss":{"version":"3.1","score":9.1,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"},"cwe":[],"affected":["squid-cache/squid","canonical/ubuntu linux","fedoraproject/fedora","opensuse/leap","debian/debian linux"],"epss":{"score":0.04302,"percentile":0.91092,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (4.30%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"http://lists.opensuse.org/opensuse-security-announce/2019-11/msg00056.html","tags":["Broken Link"],"source":"cve@mitre.org"},{"url":"http://www.squid-cache.org/Advisories/SQUID-2019_8.txt","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://bugzilla.suse.com/show_bug.cgi?id=1156329","tags":["Issue Tracking","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://lists.debian.org/debian-lts-announce/2020/07/msg00009.html","tags":["Mailing List","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MTM74TU2BSLT5B3H4F3UDW53672NVLMC/","source":"cve@mitre.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UEMOYTMCCFWK5NOXSXEIH5D2VGWVXR67/","source":"cve@mitre.org"},{"url":"https://usn.ubuntu.com/4213-1/","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://usn.ubuntu.com/4446-1/","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://www.debian.org/security/2020/dsa-4682","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2019-11/msg00056.html","tags":["Broken Link"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.squid-cache.org/Advisories/SQUID-2019_8.txt","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://bugzilla.suse.com/show_bug.cgi?id=1156329","tags":["Issue Tracking","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2020/07/msg00009.html","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MTM74TU2BSLT5B3H4F3UDW53672NVLMC/","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UEMOYTMCCFWK5NOXSXEIH5D2VGWVXR67/","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://usn.ubuntu.com/4213-1/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://usn.ubuntu.com/4446-1/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.debian.org/security/2020/dsa-4682","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2019-12523","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}