Vulnerability Note VU#962459

TCP implementations vulnerable to Denial of Service

Original Release date: 06 Aug 2018 | Last revised: 14 Sep 2018


The Linux kernel versions 4.9+ and supported versions of FreeBSD are vulnerable to denial of service conditions with low rates of specially modified packets.


CWE-400: Uncontrolled Resource Consumption ('Resource Exhaustion') - CVE-2018-5390

Linux kernel versions 4.9+ can be forced to make very expensive calls to tcp_collapse_ofo_queue() and tcp_prune_ofo_queue() for every incoming packet which can lead to a denial of service.

CWE-400: Uncontrolled Resource Consumption ('Resource Exhaustion') - CVE-2018-6922
A TCP data structure in supported versions of FreeBSD (11, 11.1, 11.2, 10, and 10.4) use an inefficient algorithm to reassemble the data.

For both vulnerabilities, an attacker can induce a denial of service condition by sending specially modified packets within ongoing TCP sessions. Maintaining the denial of service condition requires continuous two-way TCP sessions to a reachable open port. Thus, the attacks cannot be performed using spoofed IP addresses.


An remote attacker may be able to trigger a denial-of-service condition against a system with an available open port.


Apply a patch
Patches for the Linux kernel are available to address the vulnerability.
Patches for FreeBSD are available to address the vulnerability.

Vendor Information (Learn More)

VendorStatusDate NotifiedDate Updated
ADTRANAffected23 Jul 201814 Sep 2018
Akamai Technologies, Inc.Affected27 Jul 201808 Aug 2018
AmazonAffected23 Jul 201814 Sep 2018
Arista Networks, Inc.Affected23 Jul 201807 Aug 2018
Check Point Software TechnologiesAffected23 Jul 201813 Sep 2018
Debian GNU/LinuxAffected23 Jul 201807 Aug 2018
F5 Networks, Inc.Affected23 Jul 201809 Aug 2018
FreeBSD ProjectAffected23 Jul 201808 Aug 2018
Juniper NetworksAffected23 Jul 201807 Aug 2018
UbuntuAffected23 Jul 201807 Aug 2018
BroadcomNot Affected23 Jul 201811 Sep 2018
SUSE LinuxNot Affected23 Jul 201814 Sep 2018
ZyxelNot Affected23 Jul 201816 Aug 2018
3com IncUnknown23 Jul 201823 Jul 2018
A10 NetworksUnknown27 Jul 201827 Jul 2018
If you are a vendor and your product is affected, let us know.View More »

CVSS Metrics (Learn More)

Group Score Vector
Base 7.1 AV:N/AC:M/Au:N/C:N/I:N/A:C
Temporal 6.4 E:POC/RL:ND/RC:C
Environmental 6.4 CDP:ND/TD:H/CR:ND/IR:ND/AR:ND



Thanks to Juha-Matti Tilli (Aalto University, Department of Communications and Networking / Nokia Bell Labs) for reporting these vulnerabilities.

This document was written by Trent Novelly.

Other Information

  • CVE IDs: CVE-2018-5390 CVE-2018-6922
  • Date Public: 23 Jul 2018
  • Date First Published: 06 Aug 2018
  • Date Last Updated: 14 Sep 2018
  • Document Revision: 29


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