CVE-2019-11479

high-risk
Published 2019-06-19

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.

Do I need to act?

!
13.4% chance of exploitation in next 30 days
EPSS score — higher than 87% of all CVEs
-
Not on CISA KEV list
No confirmed active exploitation reported to CISA
?
Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
7
CVSS 7.5/10 High
NETWORK / LOW complexity

Affected Products (20)

Affected Vendors

Redhat Linux F5 Canonical

References (56)

Third Party Advisory http://www.arubanetworks.com/assets/alert/ARUBA-PSA-2020-010.txt
Mailing List http://www.openwall.com/lists/oss-security/2019/06/28/2
Mailing List http://www.openwall.com/lists/oss-security/2019/07/06/3
Mailing List http://www.openwall.com/lists/oss-security/2019/07/06/4
Third Party Advisory http://www.securityfocus.com/bid/108818
Third Party Advisory https://access.redhat.com/errata/RHSA-2019:1594
Third Party Advisory https://access.redhat.com/errata/RHSA-2019:1602
Third Party Advisory https://access.redhat.com/errata/RHSA-2019:1699
Third Party Advisory https://access.redhat.com/security/vulnerabilities/tcpsack
Third Party Advisory https://cert-portal.siemens.com/productcert/pdf/ssa-462066.pdf
Mailing List https://git.kernel.org/pub/scm/linux/kernel/git/davem/net.git/commit/?id=5f3e2bf...
Mailing List https://git.kernel.org/pub/scm/linux/kernel/git/davem/net.git/commit/?id=967c05a...
Patch https://github.com/Netflix/security-bulletins/blob/master/advisories/third-party...
Third Party Advisory https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44193
Third Party Advisory https://kc.mcafee.com/corporate/index?page=content&id=SB10287
Third Party Advisory https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2019-0008
Third Party Advisory https://security.netapp.com/advisory/ntap-20190625-0001/
Third Party Advisory https://support.f5.com/csp/article/K35421172
https://support.f5.com/csp/article/K35421172?utm_source=f5support&amp%3Butm_medi...
Third Party Advisory https://usn.ubuntu.com/4041-1/
and 36 more references
59
/ 100
high-risk
Severity 26/34 · High
Exploitability 12/34 · Low
Exposure 21/34 · High