CVE-2020-29661: Use After Free

Published Dec 4, 2020
·
Updated

A locking issue was discovered in the tty subsystem of the Linux kernel in drivers/tty/ttyjobctrl.c which could allow an attacker with a local account to possibly corrupt memory or escalate privileges.

Reference and upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=54ffccbf053b5b6ca4f6e45094b942fab92a25fc

Other sources

A locking issue was discovered in the tty subsystem of the Linux kernel through 5.9.13. drivers/tty/ttyjobctrl.c allows a use-after-free attack against TIOCSPGRP, aka CID-54ffccbf053b.

A locking vulnerability was found in the tty subsystem of the Linux kernel in drivers/tty/ttyjobctrl.c. This flaw allows a local attacker to possibly corrupt memory or escalate privileges. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.

In tiocspgrp of ttyjobctrl.c, there is a possible use after free due to a race condition. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.

— OSV

Affected Software

52 affected componentsFixes available
redhat/kernel<0:2.6.32-754.39.1.el6
0:2.6.32-754.39.1.el6
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-alt<0:4.14.0-115.35.1.el7a
0:4.14.0-115.35.1.el7a
redhat/kernel<0:3.10.0-1160.21.1.el7
0:3.10.0-1160.21.1.el7
redhat/kernel<0:3.10.0-693.87.1.el7
0:3.10.0-693.87.1.el7
redhat/kernel<0:3.10.0-957.70.1.el7
0:3.10.0-957.70.1.el7
redhat/kernel<0:3.10.0-1062.46.1.el7
0:3.10.0-1062.46.1.el7
redhat/kernel-rt<0:4.18.0-240.15.1.rt7.69.el8_3
0:4.18.0-240.15.1.rt7.69.el8_3
redhat/kernel<0:4.18.0-240.15.1.el8_3
0:4.18.0-240.15.1.el8_3
redhat/kernel<0:4.18.0-147.43.1.el8_1
0:4.18.0-147.43.1.el8_1
redhat/kernel-rt<0:4.18.0-193.46.1.rt13.96.el8_2
0:4.18.0-193.46.1.rt13.96.el8_2
redhat/kernel<0:4.18.0-193.46.1.el8_2
0:4.18.0-193.46.1.el8_2
Linux Linux kernel>=2.6.26<4.4.248
Linux Linux kernel>=4.5<4.9.248
Linux Linux kernel>=4.10<4.14.212
Linux Linux kernel>=4.15<4.19.163
Linux Linux kernel>=4.20<5.4.83
Linux Linux kernel>=5.5<5.9.14
Fedoraproject Fedora=32
Fedoraproject Fedora=33
Debian Debian Linux=9.0
Debian Debian Linux=10.0
NetApp Active Iq Unified Manager Vmware Vsphere
Broadcom Fabric Operating System
All of the following
NetApp Solidfire Baseboard Management Controller Firmware
NetApp Solidfire Baseboard Management Controller
All of the following
NetApp H410c Firmware
NetApp H410c
All of the following
NetApp A700s Firmware
NetApp A700s
All of the following
NetApp 8300 Firmware
NetApp 8300
All of the following
NetApp 8700 Firmware
NetApp 8700
All of the following
NetApp A400 Firmware
NetApp A400
Oracle Tekelec Platform Distribution>=7.4.0<=7.7.1
NetApp Solidfire Baseboard Management Controller Firmware
NetApp Solidfire Baseboard Management Controller
NetApp H410c Firmware
NetApp H410c
NetApp A700s Firmware
NetApp A700s
NetApp 8300 Firmware
NetApp 8300
NetApp 8700 Firmware
NetApp 8700
NetApp A400 Firmware
NetApp A400
debian/linux
5.10.223-15.10.234-16.1.129-16.1.135-16.12.25-16.12.27-1
Google Android
android/:linux_kernel:>=:0<:2021-05-05
:2021-05-05

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade redhat/kernel to a version that resolves this vulnerability.

    Fixed in 0:2.6.32-754.39.1.el6
  2. Upgrade

    Upgrade redhat/kernel-rt to a version that resolves this vulnerability.

    Fixed in 0:3.10.0-1160.21.1.rt56.1158.el7
  3. Upgrade

    Upgrade redhat/kernel-alt to a version that resolves this vulnerability.

    Fixed in 0:4.14.0-115.35.1.el7a
  4. Upgrade

    Upgrade redhat/kernel to a version that resolves this vulnerability.

    Fixed in 0:3.10.0-1160.21.1.el7
  5. Upgrade

    Upgrade redhat/kernel to a version that resolves this vulnerability.

    Fixed in 0:3.10.0-693.87.1.el7
  6. Upgrade

    Upgrade redhat/kernel to a version that resolves this vulnerability.

    Fixed in 0:3.10.0-957.70.1.el7
  7. Upgrade

    Upgrade redhat/kernel to a version that resolves this vulnerability.

    Fixed in 0:3.10.0-1062.46.1.el7
  8. Upgrade

    Upgrade redhat/kernel-rt to a version that resolves this vulnerability.

    Fixed in 0:4.18.0-240.15.1.rt7.69.el8_3
  9. Upgrade

    Upgrade redhat/kernel to a version that resolves this vulnerability.

    Fixed in 0:4.18.0-240.15.1.el8_3
  10. Upgrade

    Upgrade redhat/kernel to a version that resolves this vulnerability.

    Fixed in 0:4.18.0-147.43.1.el8_1
  11. Upgrade

    Upgrade redhat/kernel-rt to a version that resolves this vulnerability.

    Fixed in 0:4.18.0-193.46.1.rt13.96.el8_2
  12. Upgrade

    Upgrade redhat/kernel to a version that resolves this vulnerability.

    Fixed in 0:4.18.0-193.46.1.el8_2
  13. Upgrade

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

    Fixed in 5.10.223-1Fixed in 5.10.234-1Fixed in 6.1.129-1Fixed in 6.1.135-1Fixed in 6.12.25-1Fixed in 6.12.27-1
  14. Upgrade

    Upgrade android/:linux_kernel: to a version that resolves this vulnerability.

    Fixed in :2021-05-05

Event History

Dec 4, 2020
CVE Published
12:00 AM
Dec 9, 2020
CVE Published
via MITRE·04:57 PM
Data Sourced
via MITRE·04:57 PM
Description
Dec 10, 2020
Data Sourced
via Red Hat·05:42 PM
DescriptionSeverityAffected Software
May 1, 2021
Advisory Published
via OSV·12:00 AM
Data Sourced
via OSV·12:00 AM
DescriptionAffected Software
May 3, 2021
Data Sourced
via Android·12:00 AM
SeverityWeaknessAffected Software
Aug 5, 2024
Exploit Published
via GitHub·06:15 AM

Parent advisories

This vulnerability appears in the following advisories.

Frequently Asked Questions

1

What is the severity of CVE-2020-29661?

CVE-2020-29661 is classified as a high severity vulnerability that could allow an attacker to corrupt memory or escalate privileges.

2

How can I fix CVE-2020-29661?

To mitigate CVE-2020-29661, update your Linux kernel to the patched versions provided by your Linux distribution.

3

What versions of the Linux kernel are affected by CVE-2020-29661?

CVE-2020-29661 affects multiple versions of the Linux kernel, particularly those prior to the patched releases mentioned in your distribution's advisory.

4

Is CVE-2020-29661 exploitable remotely?

CVE-2020-29661 is not considered remotely exploitable; it requires local access to the affected system.

5

Are there any specific distributions affected by CVE-2020-29661?

Yes, CVE-2020-29661 impacts various distributions including Red Hat, Fedora, and Debian.

Company

Resources

Contact

SecAlerts Pty Ltd.
132 Wickham Terrace
Fortitude Valley,
QLD 4006, Australia
info@secalerts.co
By using SecAlerts services, you agree to our services end-user license agreement. This website is safeguarded by reCAPTCHA and governed by the Google Privacy Policy and Terms of Service. All names, logos, and brands of products are owned by their respective owners, and any usage of these names, logos, and brands for identification purposes only does not imply endorsement. If you possess any content that requires removal, please get in touch with us.
© 2026 SecAlerts Pty Ltd.
ABN: 70 645 966 203, ACN: 645 966 203