{"id":"CVE-2019-11479","url":"https://www.cyber-defence.io/tools/cve/CVE-2019-11479","generatedAt":"2026-10-29T00:06:02.048Z","title":"Jonathan Looney discovered that the Linux kernel default MSS is hard-coded to 48 bytes.","description":"Jonathan Looney discovered that the Linux kernel default MSS is hard-coded to 48 bytes. This allows a remote peer to fragment TCP resend queues significantly more than if a larger MSS were enforced. A remote attacker could use this to cause a denial of service. This has been fixed in stable kernel releases 4.4.182, 4.9.182, 4.14.127, 4.19.52, 5.1.11, and is fixed in commits 967c05aee439e6e5d7d805e195b3a20ef5c433d6 and 5f3e2bf008c2221478101ee72f5cb4654b9fc363.","published":"2019-06-19T00:15:13.000Z","lastModified":"2026-06-17T02:12:59.000Z","status":"Modified","sourceIdentifier":"security@ubuntu.com","cvss":{"version":"3.1","score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"cwe":["CWE-405","CWE-770"],"affected":["linux/linux kernel","f5/big-ip advanced firewall manager","f5/big-ip access policy manager","f5/big-ip application acceleration manager","f5/big-ip link controller","f5/big-ip policy enforcement manager","f5/big-ip webaccelerator","f5/big-ip application security manager","f5/big-ip local traffic manager","f5/big-ip fraud protection service","f5/big-ip global traffic manager","f5/big-ip analytics","f5/big-ip edge gateway","f5/big-ip domain name system","canonical/ubuntu linux","redhat/enterprise linux","f5/big-iq centralized management","f5/enterprise manager","f5/iworkflow","f5/traffix signaling delivery controller","redhat/virtualization host"],"epss":{"score":0.9166,"percentile":0.99813,"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":"urgent","text":"EPSS puts the probability of exploitation in the next 30 days at 91.7%, higher than 100% of all known CVEs. Patch or mitigate before the next change window."},"changes":[],"references":[{"url":"http://www.arubanetworks.com/assets/alert/ARUBA-PSA-2020-010.txt","tags":["Third Party Advisory"],"source":"security@ubuntu.com"},{"url":"http://www.openwall.com/lists/oss-security/2019/06/28/2","tags":["Mailing List","Third Party Advisory"],"source":"security@ubuntu.com"},{"url":"http://www.openwall.com/lists/oss-security/2019/07/06/3","tags":["Mailing List","Third Party Advisory"],"source":"security@ubuntu.com"},{"url":"http://www.openwall.com/lists/oss-security/2019/07/06/4","tags":["Mailing List","Third Party Advisory"],"source":"security@ubuntu.com"},{"url":"http://www.securityfocus.com/bid/108818","tags":["Third Party Advisory","VDB Entry"],"source":"security@ubuntu.com"},{"url":"https://access.redhat.com/errata/RHSA-2019:1594","tags":["Third Party Advisory"],"source":"security@ubuntu.com"},{"url":"https://access.redhat.com/errata/RHSA-2019:1602","tags":["Third Party Advisory"],"source":"security@ubuntu.com"},{"url":"https://access.redhat.com/errata/RHSA-2019:1699","tags":["Third Party Advisory"],"source":"security@ubuntu.com"},{"url":"https://access.redhat.com/security/vulnerabilities/tcpsack","tags":["Third Party Advisory"],"source":"security@ubuntu.com"},{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-462066.pdf","tags":["Third Party Advisory"],"source":"security@ubuntu.com"},{"url":"https://git.kernel.org/pub/scm/linux/kernel/git/davem/net.git/commit/?id=5f3e2bf008c2221478101ee72f5cb4654b9fc363","tags":["Mailing List","Patch","Vendor Advisory"],"source":"security@ubuntu.com"},{"url":"https://git.kernel.org/pub/scm/linux/kernel/git/davem/net.git/commit/?id=967c05aee439e6e5d7d805e195b3a20ef5c433d6","tags":["Mailing List","Patch","Vendor Advisory"],"source":"security@ubuntu.com"},{"url":"https://github.com/Netflix/security-bulletins/blob/master/advisories/third-party/2019-001.md","tags":["Patch","Third Party Advisory"],"source":"security@ubuntu.com"},{"url":"https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44193","tags":["Third Party Advisory"],"source":"security@ubuntu.com"},{"url":"https://kc.mcafee.com/corporate/index?page=content&id=SB10287","tags":["Third Party Advisory"],"source":"security@ubuntu.com"},{"url":"https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2019-0008","tags":["Third Party Advisory"],"source":"security@ubuntu.com"},{"url":"https://security.netapp.com/advisory/ntap-20190625-0001/","tags":["Third Party Advisory"],"source":"security@ubuntu.com"},{"url":"https://support.f5.com/csp/article/K35421172","tags":["Third Party Advisory"],"source":"security@ubuntu.com"},{"url":"https://support.f5.com/csp/article/K35421172?utm_source=f5support&amp%3Butm_medium=RSS","source":"security@ubuntu.com"},{"url":"https://usn.ubuntu.com/4041-1/","tags":["Third Party Advisory"],"source":"security@ubuntu.com"},{"url":"https://usn.ubuntu.com/4041-2/","tags":["Third Party Advisory"],"source":"security@ubuntu.com"},{"url":"https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/SACKPanic","tags":["Mitigation","Third Party Advisory"],"source":"security@ubuntu.com"},{"url":"https://www.kb.cert.org/vuls/id/905115","tags":["Third Party Advisory","US Government Resource"],"source":"security@ubuntu.com"},{"url":"https://www.oracle.com/security-alerts/cpujan2020.html","tags":["Third Party Advisory"],"source":"security@ubuntu.com"},{"url":"https://www.oracle.com/security-alerts/cpuoct2020.html","source":"security@ubuntu.com"},{"url":"https://www.synology.com/security/advisory/Synology_SA_19_28","tags":["Third Party Advisory"],"source":"security@ubuntu.com"},{"url":"https://www.us-cert.gov/ics/advisories/icsa-19-253-03","tags":["Third Party Advisory","US Government Resource"],"source":"security@ubuntu.com"},{"url":"https://www.us-cert.gov/ics/advisories/icsma-20-170-06","tags":["Third Party Advisory","US Government Resource"],"source":"security@ubuntu.com"},{"url":"http://www.arubanetworks.com/assets/alert/ARUBA-PSA-2020-010.txt","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.openwall.com/lists/oss-security/2019/06/28/2","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.openwall.com/lists/oss-security/2019/07/06/3","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.openwall.com/lists/oss-security/2019/07/06/4","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.securityfocus.com/bid/108818","tags":["Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://access.redhat.com/errata/RHSA-2019:1594","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://access.redhat.com/errata/RHSA-2019:1602","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://access.redhat.com/errata/RHSA-2019:1699","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://access.redhat.com/security/vulnerabilities/tcpsack","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-462066.pdf","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/pub/scm/linux/kernel/git/davem/net.git/commit/?id=5f3e2bf008c2221478101ee72f5cb4654b9fc363","tags":["Mailing List","Patch","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/pub/scm/linux/kernel/git/davem/net.git/commit/?id=967c05aee439e6e5d7d805e195b3a20ef5c433d6","tags":["Mailing List","Patch","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/Netflix/security-bulletins/blob/master/advisories/third-party/2019-001.md","tags":["Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44193","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://kc.mcafee.com/corporate/index?page=content&id=SB10287","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2019-0008","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.netapp.com/advisory/ntap-20190625-0001/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://support.f5.com/csp/article/K35421172","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://support.f5.com/csp/article/K35421172?utm_source=f5support&amp%3Butm_medium=RSS","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://usn.ubuntu.com/4041-1/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://usn.ubuntu.com/4041-2/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/SACKPanic","tags":["Mitigation","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.kb.cert.org/vuls/id/905115","tags":["Third Party Advisory","US Government Resource"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com/security-alerts/cpujan2020.html","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com/security-alerts/cpuoct2020.html","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.synology.com/security/advisory/Synology_SA_19_28","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.us-cert.gov/ics/advisories/icsa-19-253-03","tags":["Third Party Advisory","US Government Resource"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.us-cert.gov/ics/advisories/icsma-20-170-06","tags":["Third Party Advisory","US Government Resource"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2019-11479","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."}