CVE-2020-25656: Use After Free

Published Oct 15, 2020
·
Updated

A flaw was found in Linux Kernel, where a race in KDGKBSENT and KDSKBSENT leads to use-after-free read in vtdokdgkbioctl

References: https://groups.google.com/g/syzkaller-bugs/c/kZsmxkpq3UI/m/J35PFexWBgAJ?pli=1

Other sources

A flaw was found in the Linux kernel. A use-after-free was found in the way the console subsystem was using ioctls KDGKBSENT and KDSKBSENT. A local user could use this flaw to get read memory access out of bounds. The highest threat from this vulnerability is to data confidentiality.

Linux Kernel is vulnerable to a denial of service, caused by a use-after-free in the vtdokdgkbioctl function. By executing a specially-crafted program, a local authenticated attacker could exploit this vulnerability to cause the system to crash.

IBM

Affected Software

19 affected componentsFixes available
redhat/kernel-rt<0:3.10.0-1160.21.1.rt56.1158.el7
0:3.10.0-1160.21.1.rt56.1158.el7
redhat/kernel<0:3.10.0-1160.21.1.el7
0:3.10.0-1160.21.1.el7
redhat/kernel<5.10
5.10
Linux Linux kernel<5.10
Linux Linux kernel=5.10-rc1
redhat Enterprise Linux=7.0
redhat Enterprise Linux=8.0
Debian Debian Linux=9.0
Starwindsoftware Starwind Virtual San Vsphere=v8-build12533
Starwindsoftware Starwind Virtual San Vsphere=v8-build12658
Starwindsoftware Starwind Virtual San Vsphere=v8-build12859
Starwindsoftware Starwind Virtual San Vsphere=v8-build13170
Starwindsoftware Starwind Virtual San Vsphere=v8-build13586
Starwindsoftware Starwind Virtual San Vsphere=v8-build13861
IBM Security Verify Governance<=ISVG 10.0.2
IBM Security Verify Governance, Identity Manager Software Stack<=ISVG 10.0.2
IBM Security Verify Governance, Identity Manager Virtual Appliance<=ISVG 10.0.2
IBM Security Verify Governance Identity Manager Container<=ISVG 10.0.2
debian/linux
5.10.223-15.10.234-16.1.129-16.1.135-16.12.25-1

Event History

Oct 16, 2020
CVE Published
12:00 AM
Dec 2, 2020
CVE Published
via MITRE·12:00 AM
Data Sourced
via MITRE·12:00 AM
DescriptionWeakness
Jan 11, 2024
Data Sourced
via Launchpad·11:46 PM
Description
Apr 28, 2025
Data Sourced
via Ubuntu·04:22 AM
RemedyDescriptionSeverityAffected Software
May 6, 2025
Data Sourced
via Debian·04:25 AM
DescriptionAffected Software

Parent advisories

This vulnerability appears in the following advisories.

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Frequently Asked Questions

1

What is the severity of CVE-2020-25656?

CVE-2020-25656 has a medium severity rating due to the potential for a use-after-free vulnerability in the Linux Kernel.

2

How do I fix CVE-2020-25656?

To fix CVE-2020-25656, update your Linux Kernel to the recommended versions, such as 5.10 or apply specific patches provided by your distribution.

3

Which systems are affected by CVE-2020-25656?

CVE-2020-25656 affects various versions of the Linux Kernel, particularly those in Red Hat Enterprise Linux 7, 8, and Debian 9.0, among others.

4

What is the exploitability of CVE-2020-25656?

CVE-2020-25656 is considered exploitable under specific conditions where a race condition may lead to unauthorized memory access.

5

Are there any known mitigations for CVE-2020-25656?

Currently, the primary mitigation for CVE-2020-25656 is to ensure that relevant software is updated to patched versions that address the vulnerability.

Contact

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