CVE-2018-16884: Use After Free

Published Nov 27, 2018
·
Updated

A flaw was found in the Linux kernel in the NFS41+ subsystem. NFS41+ shares mounted in different network namespaces at the same time can make bcsvcprocess() use wrong back-channel id and cause a use-after-free. Thus a malicious container user can cause a host kernel memory corruption and a system panic. Due to the nature of the flaw, privilege escalation cannot be fully ruled out, although we believe it is unlikely.

References:

https://seclists.org/oss-sec/2018/q4/267

A proposed patchset:

https://patchwork.kernel.org/cover/10733767/

https://patchwork.kernel.org/patch/10733769/

Other sources

A flaw was found in the Linux kernel's NFS41+ subsystem. NFS41+ shares mounted in different network namespaces at the same time can make bcsvcprocess() use wrong back-channel IDs and cause a use-after-free vulnerability. Thus a malicious container user can cause a host kernel memory corruption and a system panic. Due to the nature of the flaw, privilege escalation cannot be fully ruled out.

Affected Software

21 affected componentsFixes available
redhat/kernel-rt<0:3.10.0-957.27.2.rt56.940.el7
0:3.10.0-957.27.2.rt56.940.el7
redhat/kernel<0:3.10.0-957.27.2.el7
0:3.10.0-957.27.2.el7
redhat/kernel-alt<0:4.14.0-115.26.1.el7a
0:4.14.0-115.26.1.el7a
redhat/kernel<0:3.10.0-693.58.1.el7
0:3.10.0-693.58.1.el7
redhat/kernel-rt<0:4.18.0-147.rt24.93.el8
0:4.18.0-147.rt24.93.el8
redhat/kernel<0:4.18.0-147.el8
0:4.18.0-147.el8
redhat/kernel<0:4.18.0-80.15.1.el8_0
0:4.18.0-80.15.1.el8_0
redhat/kernel-rt<1:3.10.0-693.58.1.rt56.652.el6
1:3.10.0-693.58.1.rt56.652.el6
Linux Linux kernel>=3.7<3.16.65
Linux Linux kernel>=3.17<3.18.133
Linux Linux kernel>=3.19<4.4.171
Linux Linux kernel>=4.5<4.9.151
Linux Linux kernel>=4.10<4.14.94
Linux Linux kernel>=4.15<4.19.16
Linux Linux kernel>=4.20<4.20.3
redhat Enterprise Linux=7.0
redhat Enterprise MRG=2.0
Debian Debian Linux=8.0
Canonical Ubuntu Linux=14.04
Canonical Ubuntu Linux=16.04
debian/linux
5.10.223-15.10.262-16.1.176-16.1.180-16.12.94-16.12.101-17.1.7-17.1.8-1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

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

    Fixed in 0:3.10.0-957.27.2.rt56.940.el7
  2. Upgrade

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

    Fixed in 0:3.10.0-957.27.2.el7
  3. Upgrade

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

    Fixed in 0:4.14.0-115.26.1.el7a
  4. Upgrade

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

    Fixed in 0:3.10.0-693.58.1.el7
  5. Upgrade

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

    Fixed in 0:4.18.0-147.rt24.93.el8
  6. Upgrade

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

    Fixed in 0:4.18.0-147.el8
  7. Upgrade

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

    Fixed in 0:4.18.0-80.15.1.el8_0
  8. Upgrade

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

    Fixed in 1:3.10.0-693.58.1.rt56.652.el6
  9. Upgrade

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

    Fixed in 5.10.223-1Fixed in 5.10.262-1Fixed in 6.1.176-1Fixed in 6.1.180-1Fixed in 6.12.94-1Fixed in 6.12.101-1Fixed in 7.1.7-1Fixed in 7.1.8-1

Event History

Nov 27, 2018
CVE Published
12:00 AM
Dec 18, 2018
Data Sourced
via Red Hat·08:54 AM
DescriptionSeverityAffected Software
CVE Published
via MITRE·10:00 PM
Data Sourced
via MITRE·10:00 PM
DescriptionSeverityWeakness
Data Sourced
via NVD·10:29 PM
RemedyDescriptionSeverityWeaknessAffected Software
Jan 11, 2024
Data Sourced
via Launchpad·10:54 PM
Description
Jul 4, 2026
Data Sourced
via Ubuntu·11:03 AM
RemedyDescriptionSeverityAffected Software
Aug 12, 2026
Data Sourced
via Debian·11:00 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-2018-16884?

CVE-2018-16884 is considered a critical vulnerability due to its potential to cause kernel memory corruption.

2

How do I fix CVE-2018-16884?

To fix CVE-2018-16884, update the kernel to one of the patched versions specified by your distribution, such as kernel-rt or kernel for Red Hat and Debian.

3

What systems are affected by CVE-2018-16884?

CVE-2018-16884 affects various Linux kernel versions, particularly those in Red Hat and Debian distributions.

4

What kind of exploit is associated with CVE-2018-16884?

CVE-2018-16884 can be exploited by a malicious container user to cause a use-after-free condition and potential kernel memory corruption.

5

Is my kernel version safe from CVE-2018-16884?

To determine if your kernel version is safe from CVE-2018-16884, compare it with the known vulnerable versions listed in security advisories.

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