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CVE-2020-12656

16
FAUCET Score

CVE-2020-12656 is a memory leak vulnerability in the Linux kernel's rpcsec_gss_krb5 implementation, specifically affecting versions through 5.6.10, including various Canonical, Linux, and openSUSE distributions. This flaw, rated Medium (CVSS 5.5), stems from missing domain_release calls, leading to memory exhaustion (Availability impact). While loading kernel modules is a privileged operation, allowing a privileged attacker to cause a denial of service, there is no evidence of active exploitation, public exploit code, or significant community discussion surrounding this vulnerability.

Impacted Technologies

VendorProductVersion(s)CPE
<= 5.6.10CPE matchmatch criteria
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
14.04CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:esm:*:*:*
16.04CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:esm:*:*:*
18.04CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*
20.04CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:20.04:*:*:*:lts:*:*:*

CVSS Data

CVSS version used by this source: 3.1

5.5MEDIUM

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

Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
1.8
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.33%
Probability of exploitation in next 30 days
EPSS Percentile
25.9%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0033 is in the 83rd percentile among its peer group of 15,940 CVEs.

Social Chatter

No social media mentions found for this CVE.

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.0 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (9)

microsoftpatch availablevia msrc
Product: 17036-16820Fixed in: 5.4.91-3
microsoftpatch availablevia msrc
Product: CBL Mariner 1.0 x64Fixed in: 5.4.91-3
microsoftpatch availablevia msrc
Product: CBL Mariner 1.0 ARMFixed in: 5.4.91-3
microsoftpatch availablevia msrc
Product: cm1 kernel 5.4.91-3 on CBL Mariner 1.0Fixed in: 5.4.91-3
redhatvendor investigatingvia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: kernel
redhatvendor investigatingvia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: kernel-alt
redhatvendor investigatingvia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: kernel-rt
redhatno patchvia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: kernel
redhatno patchvia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: kernel-rt

Vendor Advisories (3)

microsoft2020-Aug/CVE-2020-12656

CVE-2020-12656

Aug 11, 2020
microsoft2020-May/CVE-2020-12656Moderate

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

May 12, 2020
redhatCVE-2020-12656Low

kernel: gss_mech_free in net/sunrpc/auth_gss/gss_mech_switch.c in the rpcsec_gss_krb5 implementation lacks certain domain_release calls, leading to a memory leak.

May 5, 2020

References

lists.opensuse.org / opensuse-security-announce/2020-06/msg00022.html
Mailing ListThird Party Advisory
lists.opensuse.org / opensuse-security-announce/2020-07/msg00008.html
Mailing ListThird Party Advisory
bugzilla.kernel.org / show_bug.cgi
Issue TrackingVendor Advisory
usn.ubuntu.com / 4483-1
Third Party Advisory
usn.ubuntu.com / 4485-1
Third Party Advisory