This knowledge base has moved to the documentation site. Please visit the knowledge base here for the most up to date content. This site is no longer maintained.

Spectre and Meltdown Vulnerability Fixes



Patches are available for the Spectre and Meltdown vulnerabilities that Cumulus Networks announced previously. They remedy the following vulnerabilities:

Note: This issue was announced on the Cumulus Networks security announcement mailing list on April 3, 2019.


  • This issue applies to Cumulus Linux 3.0.0 - 3.7.12 ESR only. The Spectre and Meltdown patches are enabled by default in Cumulus Linux 4.0.0 and later.

Verified Platforms

Cumulus Networks has tested and verified that the patches are available for the following platforms; the resolution listed below applies to all supported platforms:

  • Dell Z9100-ON
  • Dell Z9264F-ON
  • Edgecore AS6712-32X
  • Edgecore  AS5712-54X
  • HPE Altoline 6940
  • HPE Altoline 6920


The patches have been applied to the Cumulus Linux 3.7.4 kernel and later releases, but are disabled by default in the 3.7.x branch. They are disabled because, although we have done extensive testing, this fix includes a number of kernel changes and may impact switch performance. If you wish, you can leave this fix disabled.

You enable the patches by configuring some kernel command line options in GRUB configuration files, rebooting the switch, then updating your switch BIOS.

The command line option is in the /etc/default/grub.d/00-spectre-meltdown.cfg file. If you installed Cumulus Linux 3.7.4 from the binary installation image, the command line option also appears in /etc/default/grub.

To apply the patches, do the following:

  1. Edit the /etc/default/grub.d/00-spectre-meltdown.cfg file as follows:
    cumulus@switch:~$ sed -i "s/GRUB_CMDLINE_LINUX_DEFAULT/#GRUB_CMDLINE_LINUX_DEFAULT/" /etc/default/grub.d/00-spectre-meltdown.cfg
  2. If you did a binary install of Cumulus Linux 3.7.4 or later, you also must edit /etc/default/grub as follows:
    cumulus@switch:~$ sed -i 's/GRUB_CMDLINE_LINUX_DEFAULT="quiet noibrs noibpb nolfence spectre_v2=off nopti"/#GRUB_CMDLINE_LINUX_DEFAULT="quiet noibrs noibpb nolfence spectre_v2=off nopti"\
    GRUB_CMDLINE_LINUX_DEFAULT="quiet"/' /etc/default/grub
  3. Run update-grub:
    cumulus@switch:~$ update-grub
  4. Reboot the switch.
  5. Update the BIOS on your switch. For information on how to do this, contact your switch manufacturer.
  6. Verify that the GRUB option was successfully enabled, check /proc/cmdline to make sure the following does not exist:
    cumulus@switch:~$ grep "noibrs noibpb nolfence spectre_v2=off nopti" /proc/cmdline
    You can also verify that the GRUB option was successfully enabled by checking:
    cumulus@switch:~$ rgrep . /sys/devices/system/cpu/vulnerabilities
    /sys/devices/system/cpu/vulnerabilities/spectre_v1:Mitigation: lfence
    /sys/devices/system/cpu/vulnerabilities/spectre_v2:Mitigation: IBRS IBPB
    /sys/devices/system/cpu/vulnerabilities/meltdown:Mitigation: PTI



This support portal has moved

Cumulus Networks is now part of the NVIDIA Networking Business Unit! The NVIDIA Cumulus Global Support Services (GSS) team has merged its operations with the NVIDIA Mellanox support services team.

You can access NVIDIA Cumulus support content from the Mellanox support portal.

You open and update new cases on the Mellanox support portal. Any previous cases that have been closed have been migrated to the Mellanox support portal.

Cases that are still open on the Cumulus portal will continue to be managed on the Cumulus portal. Once these cases close, they will be moved to the Mellanox support portal.

Powered by Zendesk