{"id":"CVE-2018-18506","url":"https://www.cyber-defence.io/tools/cve/CVE-2018-18506","generatedAt":"2026-10-29T03:02:39.424Z","title":"This behavior is disallowed by default when a proxy is manually configured, but when enabled could allow for attacks on services and tools that bind to the localhost for networked behavior if they are accessed through browsing.","description":"When proxy auto-detection is enabled, if a web server serves a Proxy Auto-Configuration (PAC) file or if a PAC file is loaded locally, this PAC file can specify that requests to the localhost are to be sent through the proxy to another server. This behavior is disallowed by default when a proxy is manually configured, but when enabled could allow for attacks on services and tools that bind to the localhost for networked behavior if they are accessed through browsing. This vulnerability affects Firefox < 65.","published":"2019-02-05T21:29:01.000Z","lastModified":"2026-06-17T01:47:26.000Z","status":"Modified","sourceIdentifier":"security@mozilla.org","cvss":{"version":"3.1","score":5.9,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N"},"cwe":[],"affected":["mozilla/firefox","canonical/ubuntu linux","debian/debian linux","redhat/enterprise linux","redhat/enterprise linux desktop","redhat/enterprise linux eus","redhat/enterprise linux server","redhat/enterprise linux server aus","redhat/enterprise linux server eus","redhat/enterprise linux server tus","redhat/enterprise linux workstation","opensuse/leap"],"epss":{"score":0.02196,"percentile":0.82385,"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":"low","text":"Lower severity and a low EPSS score (2.20%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"http://lists.opensuse.org/opensuse-security-announce/2019-03/msg00035.html","tags":["Broken Link","Mailing List","Third Party Advisory"],"source":"security@mozilla.org"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2019-03/msg00043.html","tags":["Mailing List","Third Party Advisory"],"source":"security@mozilla.org"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00023.html","tags":["Mailing List","Third Party Advisory"],"source":"security@mozilla.org"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00043.html","tags":["Mailing List","Third Party Advisory"],"source":"security@mozilla.org"},{"url":"http://www.securityfocus.com/bid/106773","tags":["Broken Link","Third Party Advisory","VDB Entry"],"source":"security@mozilla.org"},{"url":"https://access.redhat.com/errata/RHSA-2019:0622","tags":["Third Party Advisory"],"source":"security@mozilla.org"},{"url":"https://access.redhat.com/errata/RHSA-2019:0623","tags":["Third Party Advisory"],"source":"security@mozilla.org"},{"url":"https://access.redhat.com/errata/RHSA-2019:0680","tags":["Third Party Advisory"],"source":"security@mozilla.org"},{"url":"https://access.redhat.com/errata/RHSA-2019:0681","tags":["Third Party Advisory"],"source":"security@mozilla.org"},{"url":"https://access.redhat.com/errata/RHSA-2019:0966","tags":["Third Party Advisory"],"source":"security@mozilla.org"},{"url":"https://access.redhat.com/errata/RHSA-2019:1144","tags":["Third Party Advisory"],"source":"security@mozilla.org"},{"url":"https://lists.debian.org/debian-lts-announce/2019/03/msg00024.html","tags":["Mailing List","Third Party Advisory"],"source":"security@mozilla.org"},{"url":"https://lists.debian.org/debian-lts-announce/2019/04/msg00000.html","tags":["Mailing List","Third Party Advisory"],"source":"security@mozilla.org"},{"url":"https://seclists.org/bugtraq/2019/Apr/0","tags":["Mailing List","Third Party Advisory"],"source":"security@mozilla.org"},{"url":"https://seclists.org/bugtraq/2019/Mar/28","tags":["Mailing List","Third Party Advisory"],"source":"security@mozilla.org"},{"url":"https://security.gentoo.org/glsa/201904-07","tags":["Third Party Advisory"],"source":"security@mozilla.org"},{"url":"https://usn.ubuntu.com/3874-1/","tags":["Third Party Advisory"],"source":"security@mozilla.org"},{"url":"https://usn.ubuntu.com/3927-1/","tags":["Third Party Advisory"],"source":"security@mozilla.org"},{"url":"https://www.debian.org/security/2019/dsa-4411","tags":["Third Party Advisory"],"source":"security@mozilla.org"},{"url":"https://www.debian.org/security/2019/dsa-4420","tags":["Third Party Advisory"],"source":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2019-01/","tags":["Vendor Advisory"],"source":"security@mozilla.org"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2019-03/msg00035.html","tags":["Broken Link","Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2019-03/msg00043.html","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00023.html","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00043.html","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.securityfocus.com/bid/106773","tags":["Broken Link","Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://access.redhat.com/errata/RHSA-2019:0622","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://access.redhat.com/errata/RHSA-2019:0623","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://access.redhat.com/errata/RHSA-2019:0680","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://access.redhat.com/errata/RHSA-2019:0681","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://access.redhat.com/errata/RHSA-2019:0966","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://access.redhat.com/errata/RHSA-2019:1144","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2019/03/msg00024.html","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2019/04/msg00000.html","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://seclists.org/bugtraq/2019/Apr/0","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://seclists.org/bugtraq/2019/Mar/28","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.gentoo.org/glsa/201904-07","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://usn.ubuntu.com/3874-1/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://usn.ubuntu.com/3927-1/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.debian.org/security/2019/dsa-4411","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.debian.org/security/2019/dsa-4420","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.mozilla.org/security/advisories/mfsa2019-01/","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2018-18506","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."}