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.
http://www.arubanetworks.com/assets/alert/ARUBA-PSA-2020-010.txt
http://www.openwall.com/lists/oss-security/2019/06/28/2
http://www.openwall.com/lists/oss-security/2019/07/06/3
http://www.openwall.com/lists/oss-security/2019/07/06/4
http://www.securityfocus.com/bid/108818
https://access.redhat.com/errata/RHSA-2019:1594
https://access.redhat.com/errata/RHSA-2019:1602
https://access.redhat.com/errata/RHSA-2019:1699
https://access.redhat.com/security/vulnerabilities/tcpsack
https://cert-portal.siemens.com/productcert/pdf/ssa-462066.pdf
https://github.com/Netflix/security-bulletins/blob/master/advisories/third-party/2019-001.md
https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44193
https://kc.mcafee.com/corporate/index?page=content&id=SB10287
https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2019-0008
https://security.netapp.com/advisory/ntap-20190625-0001/
https://support.f5.com/csp/article/K35421172
https://support.f5.com/csp/article/K35421172?utm_source=f5support&utm_medium=RSS
https://usn.ubuntu.com/4041-1/
https://usn.ubuntu.com/4041-2/
https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/SACKPanic
https://www.kb.cert.org/vuls/id/905115
https://www.oracle.com/security-alerts/cpujan2020.html
https://www.oracle.com/security-alerts/cpuoct2020.html
https://www.synology.com/security/advisory/Synology_SA_19_28
Source: MITRE
Published: 2019-06-19
Updated: 2020-10-20
Type: CWE-770
Base Score: 5
Vector: AV:N/AC:L/Au:N/C:N/I:N/A:P
Impact Score: 2.9
Exploitability Score: 10
Severity: MEDIUM
Base Score: 7.5
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Impact Score: 3.6
Exploitability Score: 3.9
Severity: HIGH