CVE-2019-11479CWE-405

Jonathan Looney discovered that the Linux kernel default MSS is hard-coded to 48 bytes

Medium · published June 18, 2019

Patch now

High probability of exploitation

CVSS calls it medium at 5.3. It sits in the 99.8th percentile for exploit probability.

CVSS v3.0
5.3
EPSS
92%
Percentile
99.8
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.0
5.3 · MEDIUM
Vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CVSS v4.0
Not supplied
EPSS
0.91660 · 99.8th percentile
Weakness
CWE-405 · Asymmetric Resource Consumption (Amplification)
Published
2019-06-18T23:34Z
EPSS history
Timeline
  • 18 JUN 23:34Z
    Jonathan Looney discovered that the Linux kernel default MSS is hard-coded to 48 bytes
    cvelistv5