{"id":"CVE-2016-4554","url":"https://www.cyber-defence.io/tools/cve/CVE-2016-4554","generatedAt":"2026-11-05T05:31:23.972Z","title":"mime_header.cc in Squid before 3.5.18 allows remote attackers to bypass intended same-origin restrictions and possibly conduct cache-poisoning attacks via a crafted HTTP Host header, aka a \"header smuggling\" issue.","description":"mime_header.cc in Squid before 3.5.18 allows remote attackers to bypass intended same-origin restrictions and possibly conduct cache-poisoning attacks via a crafted HTTP Host header, aka a \"header smuggling\" issue.","published":"2016-05-10T19:59:01.000Z","lastModified":"2026-06-17T00:47:46.000Z","status":"Modified","sourceIdentifier":"cve@mitre.org","cvss":{"version":"3.0","score":8.6,"severity":"HIGH","vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N"},"cwe":["CWE-345"],"affected":["oracle/linux","squid-cache/squid","canonical/ubuntu linux"],"epss":{"score":0.38893,"percentile":0.98593,"date":"2026-11-04","history":[{"date":"2026-09-21","score":0.39904,"percentile":0.98602},{"date":"2026-09-22","score":0.38893,"percentile":0.98522}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"urgent","text":"EPSS puts the probability of exploitation in the next 30 days at 38.9%, higher than 99% of all known CVEs. Patch or mitigate before the next change window."},"changes":[],"references":[{"url":"http://lists.opensuse.org/opensuse-security-announce/2016-08/msg00010.html","source":"cve@mitre.org"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2016-08/msg00040.html","source":"cve@mitre.org"},{"url":"http://lists.opensuse.org/opensuse-updates/2016-08/msg00069.html","source":"cve@mitre.org"},{"url":"http://www.debian.org/security/2016/dsa-3625","source":"cve@mitre.org"},{"url":"http://www.oracle.com/technetwork/topics/security/linuxbulletinapr2016-2952096.html","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://www.securitytracker.com/id/1035769","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://www.squid-cache.org/Advisories/SQUID-2016_8.txt","tags":["Vendor Advisory"],"source":"cve@mitre.org"},{"url":"http://www.squid-cache.org/Versions/v3/3.1/changesets/SQUID-2016_8.patch","tags":["Patch"],"source":"cve@mitre.org"},{"url":"http://www.squid-cache.org/Versions/v3/3.2/changesets/SQUID-2016_8.patch","tags":["Patch"],"source":"cve@mitre.org"},{"url":"http://www.squid-cache.org/Versions/v3/3.3/changesets/SQUID-2016_8.patch","tags":["Patch"],"source":"cve@mitre.org"},{"url":"http://www.squid-cache.org/Versions/v3/3.4/changesets/SQUID-2016_8.patch","tags":["Patch"],"source":"cve@mitre.org"},{"url":"http://www.squid-cache.org/Versions/v3/3.5/changesets/SQUID-2016_8.patch","tags":["Patch"],"source":"cve@mitre.org"},{"url":"http://www.ubuntu.com/usn/USN-2995-1","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://access.redhat.com/errata/RHSA-2016:1138","source":"cve@mitre.org"},{"url":"https://access.redhat.com/errata/RHSA-2016:1139","source":"cve@mitre.org"},{"url":"https://access.redhat.com/errata/RHSA-2016:1140","source":"cve@mitre.org"},{"url":"https://security.gentoo.org/glsa/201607-01","source":"cve@mitre.org"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2016-08/msg00010.html","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2016-08/msg00040.html","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://lists.opensuse.org/opensuse-updates/2016-08/msg00069.html","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.debian.org/security/2016/dsa-3625","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.oracle.com/technetwork/topics/security/linuxbulletinapr2016-2952096.html","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.securitytracker.com/id/1035769","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.squid-cache.org/Advisories/SQUID-2016_8.txt","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.squid-cache.org/Versions/v3/3.1/changesets/SQUID-2016_8.patch","tags":["Patch"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.squid-cache.org/Versions/v3/3.2/changesets/SQUID-2016_8.patch","tags":["Patch"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.squid-cache.org/Versions/v3/3.3/changesets/SQUID-2016_8.patch","tags":["Patch"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.squid-cache.org/Versions/v3/3.4/changesets/SQUID-2016_8.patch","tags":["Patch"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.squid-cache.org/Versions/v3/3.5/changesets/SQUID-2016_8.patch","tags":["Patch"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.ubuntu.com/usn/USN-2995-1","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://access.redhat.com/errata/RHSA-2016:1138","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://access.redhat.com/errata/RHSA-2016:1139","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://access.redhat.com/errata/RHSA-2016:1140","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.gentoo.org/glsa/201607-01","source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2016-4554","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."}