CVE-2020-12656 Denial of service in n/a

What is CVE-2020-12656?

CVE-2020-12656 is a medium-severity denial of service vulnerability in Canonical Ubuntu Linux, published on 5 May 2020. It can only be exploited from the same machine or local network, with no action from the victim.

Official 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

Weakness: CWE-401

Which versions are affected by CVE-2020-12656?

It affects 3 products.

Products include Canonical Ubuntu Linux, Linux kernel, Opensuse Leap.

How do I fix CVE-2020-12656?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2020-12656 being exploited?

There is no known exploitation of CVE-2020-12656 in the wild and no public exploit code.

Other vulnerabilities in Canonical Ubuntu Linux

• CVE-2020-11651 SaltStack Salt Authentication Bypass Exploited Critical 9.8
• CVE-2020-7247 OpenSMTPD Remote Code Execution Exploited Critical 9.8
• CVE-2019-16928 Exim Out-of-bounds Write Exploited Critical 9.8
• CVE-2018-6789 Exim Buffer Overflow Exploited Critical 9.8
• CVE-2015-2590 Oracle Java SE and Java SE Embedded Remote Code Execution Exploited Critical 9.8

All Canonical Ubuntu Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2020-12656, GHSA-j42j-7596-mcr4, UBUNTU-CVE-2020-12656.