SVG:Meltdown and Spectre Vulnerabilities

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Meltdown and Spectre Vulnerabilities

Purpose of this page

To provide more detailed information about the Meltdown and Spectre vulnerabilities, to complement the advisory, SVG:Advisory-SVG-CVE-2017-5753.

We are continuing to add new information when we become aware of it, and the situation continues to change (02nd February 2018).

What are they?

These are vulnerabilities in the design of the chip hardware, and cannot be fully resolved by patching operating systems. However patches are available which mitigate these problems.

  • Meltdown (CVE-2017-5754) affects most Intel chips.
  • Spectre (CVE-2017-5753 and CVE-2017-5715) affects a wide range of chips.

For more details, see , and

How to mitigate these vulnerabilities

Each CVE can be mitigated via different ways:

  • Meltdown (CVE-2017-5754) can be mitigated via Kernel Page Table Isolation, which is enabled by default in latest linux kernels
  • Spectre Variant 1 (CVE-2017-5753) has to be mitigated in each software which can be vulnerable. The latest linux kernel contains fixes to protect itself (does not protect other software).
  • Spectre Variant 2 (CVE-2017-5715) can be (at least partially) mitigated via at least two different approach:
    • Using new Intel-specific MSR, added via a microcode update, to control indirect branch restricted speculation (IBRS): Both a kernel and a microcode update are required. In addition, in case of virtualization, an update of the virtualization software (e.g. qemu & virt) is required to expose the new MSR to the VM.
    • Using "retpoline", a new software construct that can mitigate, on most CPUs, the vulnerability


As of Feb 2nd 2018, RedHat has offered new kernel updates that can mitigate Meltdown (CVE-2017-5754), Spectre Variant 1 (CVE-2017-5753) and Spectre Variant 2 (CVE-2017-5715).

However, due to instability issues, it has removed the microcode updates required for Spectre Variant 2 (CVE-2017-5715). Until Intel releases stable microcode or RedHat switches to 'retpoline', no mitigation for Spectre Variant 2 (CVE-2017-5715) is safely usable.

It is currently possible to mitigate Meltdown (CVE-2017-5754) and Spectre Variant 1 (CVE-2017-5753) by:

  • On RHEL7: Updating the kernel to 3.10.0-693.11.6.el7, see RHSA-2018:0007
  • On RHEL6: Updating the kernel to 2.6.32-696.18.7.el6, see RHSA-2018:0008


Centos is following RedHat (see above).

It is currently possible to mitigate Meltdown (CVE-2017-5754) and Spectre Variant 1 (CVE-2017-5753) by:

  • On Centos 7: Updating the kernel to 3.10.0-693.11.6.el7, see CESA-2018:0007
  • On Centos 6: Updating the kernel to 2.6.32-696.18.7.el6, see CESA-2018:0008

Scientific Linux

Scientific Linux is following RedHat (see above).

It is currently possible to mitigate Meltdown (CVE-2017-5754) and Spectre Variant 1 (CVE-2017-5753) by:

Additional details as well as information on other systems and platforms can be found in the next section.

More Information

Relevant Advisories


CERN has compiled information which is useful for many EGI sites:


Intel has initially, on January 8th, released new microcodes to complement the IBRS kernel patchset. However, these new microcodes are in fact unstable and Intel has since then recommended to stop deploying them.

Intel latest recommendation can be found in their advisory, INTEL-SA-00088

More updates and information:

Linux Distributions


Important! [as of 17th January]

RedHat has issued new microcode_ctl packages to rollback the latest updates, see RHSA-2018:0093.

RedHat description:

RedHat CVE info:


Important! [as of 17th January]

Centos seems to be following Redhat in the revert of the microcode_ctl package, see the disclaimer in the sources of the last package

CentOS 7:

CentOS 6:

See further in the centos-announce Security mails for January

Scientific Linux

Important! [as of 18th January]

Scientific Linux is following RedHat in the revert of the microcode_ctl package, see



CVE-2017-5715 CVE-2017-5753 CVE-2017-5754

System Vendors



Important! [as of 23rd January]

Dell is advising that all customers and partners should not deploy the BIOS update for the Spectre vulnerability at this time due to Intel’s advisory acknowledging reboot issues and unpredictable system behaviour.

Note this is changing rather frequently


[as of January 23]

HPE has updated their advisory to note that "Marked impacted products with TBD for System ROM updates per Intel's guidance on microcode issues" - so following suit with DELL.


[as of January 23]

Lenovo security advisory




In order to protect hypervisors from malicious VMs, the kernel, microcode and QEMU must be updated: