CVE-2020-12656: Medium severity Linux Linux kernel vulnerability

Published May 5, 2020
·
Updated

DISPUTED gssmechfree in net/sunrpc/authgss/gssmechswitch.c in the rpcsecgsskrb5 implementation in the Linux kernel through 5.6.10 lacks certain domainrelease calls, leading to a memory leak. Note: This was disputed with the assertion that the issue does not grant any access not already available. It is a problem that on unloading a specific kernel module some memory is leaked, but loading kernel modules is a privileged operation. A user could also write a kernel module to consume any amount of memory they like and load that replicating the effect of this bug.

Affected Software

8 affected componentsFixes available
Linux Linux kernel<=5.6.10
Canonical Ubuntu Linux=14.04
Canonical Ubuntu Linux=16.04
Canonical Ubuntu Linux=18.04
Canonical Ubuntu Linux=20.04
openSUSE Leap=15.1
openSUSE Leap=15.2
debian/linux
5.10.223-15.10.262-16.1.176-16.1.180-16.12.94-16.12.101-17.1.8-17.1.8-2

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade debian/linux to a version that resolves this vulnerability.

    Fixed in 5.10.223-1Fixed in 5.10.262-1Fixed in 6.1.176-1Fixed in 6.1.180-1Fixed in 6.12.94-1Fixed in 6.12.101-1Fixed in 7.1.8-1Fixed in 7.1.8-2
  2. Upgrade

    Upgrade Linux kernel (net/sunrpc/auth_gss/gss_mech_switch.c rpcsec_gss_krb5 implementation) to a version that resolves this vulnerability.

    Fixed in 5.6.10
  3. Compensating control

    Limit the ability for untrusted users to load kernel modules (since loading kernel modules is a privileged operation that could replicate the memory-consumption effect).

Event History

May 5, 2020
CVE Published
via MITRE·05:42 AM
Data Sourced
via MITRE·05:42 AM
Description
Disputed
06:15 AM
Data Sourced
via NVD·06:15 AM
DescriptionSeverityWeaknessAffected Software
Sep 11, 2025
Data Sourced
via Launchpad·03:54 AM
Description
Aug 15, 2026
Data Sourced
via Ubuntu·11:20 AM
RemedyDescriptionSeverityAffected Software
Aug 16, 2026
Data Sourced
via Debian·11:23 AM
DescriptionAffected Software

Frequently Asked Questions

1

What is the severity of CVE-2020-12656?

CVE-2020-12656 is considered a medium severity vulnerability due to the potential for memory leaks.

2

What systems are affected by CVE-2020-12656?

CVE-2020-12656 affects Linux Kernel versions up to 5.6.10 and specific versions of Ubuntu and openSUSE.

3

How do I fix CVE-2020-12656?

To fix CVE-2020-12656, upgrade to a patched version of the Linux Kernel or the relevant operating system package.

4

Is there any exploit for CVE-2020-12656?

CVE-2020-12656 does not grant new access but may lead to resource exhaustion due to a memory leak.

5

What is the impact of CVE-2020-12656?

The impact of CVE-2020-12656 includes potential denial of service caused by memory leaks affecting system stability.

Contact

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