CVE-2020-12656

Name: CVE-2020-12656
Creator: NVD / NIST
Published: 2020-05-05T06:15:11.12+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.5/10EPSS 0.33%

Last modified Jun 17, 2026

CVE-2020-12656 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. gss_mech_free in net/sunrpc/auth_gss/gss_mech_switch.c in the rpcsec_gss_krb5 implementation in the Linux kernel through 5.6.10 lacks certain domain_release calls, leading to a memory leak. Note: This was disputed with the assertion that the issue does not grant any access not already available. EPSS estimates a 0.33% chance of exploitation in the next 30 days.

Description

gss_mech_free in net/sunrpc/auth_gss/gss_mech_switch.c in the rpcsec_gss_krb5 implementation in the Linux kernel through 5.6.10 lacks certain domain_release 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

Metrics

CVSS 3.1

5.5/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

0.33%

25.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-401

Affected Software

Vendor	Product	Versions
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

References

http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00022.htmlMailing List, Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00008.htmlMailing List, Third Party Advisory
https://bugzilla.kernel.org/show_bug.cgi?id=206651Issue Tracking, Vendor Advisory
https://usn.ubuntu.com/4483-1/Third Party Advisory
https://usn.ubuntu.com/4485-1/Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00022.htmlMailing List, Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00008.htmlMailing List, Third Party Advisory
https://bugzilla.kernel.org/show_bug.cgi?id=206651Issue Tracking, Vendor Advisory
https://usn.ubuntu.com/4483-1/Third Party Advisory
https://usn.ubuntu.com/4485-1/Third Party Advisory

Timeline

Published: May 5, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-12656?

How severe is CVE-2020-12656?

CVE-2020-12656 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.33% probability of exploitation in the next 30 days.

How do I fix CVE-2020-12656?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-12656?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST