{"id":"CVE-2011-4539","url":"https://www.cyber-defence.io/tools/cve/CVE-2011-4539","generatedAt":"2026-10-27T22:04:07.699Z","title":"dhcpd in ISC DHCP 4.x before 4.2.3-P1 and 4.1-ESV before 4.1-ESV-R4 does not properly handle regular expressions in dhcpd.conf, which allows remote attackers to cause a denial of service (daemon crash) via a crafted request packet.","description":"dhcpd in ISC DHCP 4.x before 4.2.3-P1 and 4.1-ESV before 4.1-ESV-R4 does not properly handle regular expressions in dhcpd.conf, which allows remote attackers to cause a denial of service (daemon crash) via a crafted request packet.","published":"2011-12-08T11:55:02.000Z","lastModified":"2026-06-16T23:35:01.000Z","status":"Modified","sourceIdentifier":"cve@mitre.org","cvss":{"version":"2.0","score":5,"severity":"MEDIUM","vector":"AV:N/AC:L/Au:N/C:N/I:N/A:P"},"cwe":["CWE-20"],"affected":["isc/dhcp","canonical/ubuntu linux","debian/debian linux"],"epss":{"score":0.15219,"percentile":0.96733,"date":"2026-10-26","history":[]},"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 15.2%, higher than 97% of all known CVEs. Patch or mitigate before the next change window."},"changes":[],"references":[{"url":"http://lists.fedoraproject.org/pipermail/package-announce/2011-December/070980.html","tags":["Mailing List","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://lists.fedoraproject.org/pipermail/package-announce/2012-January/071549.html","tags":["Mailing List","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://lists.opensuse.org/opensuse-updates/2011-12/msg00006.html","tags":["Mailing List","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://secunia.com/advisories/47153","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://secunia.com/advisories/47178","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://security.gentoo.org/glsa/glsa-201301-06.xml","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://www.debian.org/security/2012/dsa-2519","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://www.mandriva.com/security/advisories?name=MDVSA-2011:182","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://www.securityfocus.com/bid/50971","tags":["Third Party Advisory","VDB Entry"],"source":"cve@mitre.org"},{"url":"http://www.securitytracker.com/id?1026393","tags":["Third Party Advisory","VDB Entry"],"source":"cve@mitre.org"},{"url":"http://www.ubuntu.com/usn/USN-1309-1","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://exchange.xforce.ibmcloud.com/vulnerabilities/71680","tags":["Third Party Advisory","VDB Entry"],"source":"cve@mitre.org"},{"url":"https://www.isc.org/software/dhcp/advisories/cve-2011-4539","tags":["Vendor Advisory"],"source":"cve@mitre.org"},{"url":"http://lists.fedoraproject.org/pipermail/package-announce/2011-December/070980.html","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://lists.fedoraproject.org/pipermail/package-announce/2012-January/071549.html","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://lists.opensuse.org/opensuse-updates/2011-12/msg00006.html","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://secunia.com/advisories/47153","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://secunia.com/advisories/47178","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://security.gentoo.org/glsa/glsa-201301-06.xml","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.debian.org/security/2012/dsa-2519","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.mandriva.com/security/advisories?name=MDVSA-2011:182","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.securityfocus.com/bid/50971","tags":["Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.securitytracker.com/id?1026393","tags":["Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.ubuntu.com/usn/USN-1309-1","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://exchange.xforce.ibmcloud.com/vulnerabilities/71680","tags":["Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.isc.org/software/dhcp/advisories/cve-2011-4539","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2011-4539","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."}