CVE-2020-25212: High severity Linux Linux kernel vulnerability

Published Sep 9, 2020
·
Updated

A flaw was found in the NFSv4 implementation where when mounting a remote attacker controlled server it could return specially crafted response allow for local memory corruption and possibly privilege escalation.

Other sources

A TOCTOU mismatch in the NFS client code in the Linux kernel before 5.8.3 could be used by local attackers to corrupt memory or possibly have unspecified other impact because a size check is in fs/nfs/nfs4proc.c instead of fs/nfs/nfs4xdr.c, aka CID-b4487b935452.

A TOCTOU mismatch in the NFS client code in the Linux kernel before 5.8.3 could be used by local attackers to corrupt memory or possibly have unspecified other impact because a size check is in fs/nfs/nfs4proc.c instead of fs/nfs/nfs4xdr.c.

References:

https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.8.3 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b4487b93545214a9db8cbf32e86411677b0cca21 https://twitter.com/grsecurity/status/1303370421958578179

— Red Hat

Affected Software

17 affected componentsFixes available
redhat/kernel-rt<0:3.10.0-1160.11.1.rt56.1145.el7
0:3.10.0-1160.11.1.rt56.1145.el7
redhat/kernel-alt<0:4.14.0-115.32.1.el7a
0:4.14.0-115.32.1.el7a
redhat/kernel<0:3.10.0-1160.11.1.el7
0:3.10.0-1160.11.1.el7
redhat/kernel<0:3.10.0-693.82.1.el7
0:3.10.0-693.82.1.el7
redhat/kernel<0:3.10.0-957.70.1.el7
0:3.10.0-957.70.1.el7
redhat/kernel<0:3.10.0-1062.45.1.el7
0:3.10.0-1062.45.1.el7
redhat/kernel-rt<0:4.18.0-305.rt7.72.el8
0:4.18.0-305.rt7.72.el8
redhat/kernel<0:4.18.0-305.el8
0:4.18.0-305.el8
Linux Linux kernel<5.8.3
Debian Debian Linux=9.0
openSUSE Leap=15.1
openSUSE Leap=15.2
Canonical Ubuntu Linux=14.04
Canonical Ubuntu Linux=16.04
Canonical Ubuntu Linux=18.04
Canonical Ubuntu Linux=20.04
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 0:3.10.0-1160.11.1.rt56.1145.el7
  2. Upgrade

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

    Fixed in 0:4.14.0-115.32.1.el7a
  3. Upgrade

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

    Fixed in 0:3.10.0-1160.11.1.el7
  4. Upgrade

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

    Fixed in 0:3.10.0-693.82.1.el7
  5. Upgrade

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

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

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

    Fixed in 0:3.10.0-1062.45.1.el7
  7. Upgrade

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

    Fixed in 0:4.18.0-305.rt7.72.el8
  8. Upgrade

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

    Fixed in 0:4.18.0-305.el8
  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
  10. Upgrade

    Upgrade linux kernel to a version that resolves this vulnerability.

    Fixed in 5.8.3
  11. Compensating control

    Configure authentication and only mount authenticated NFSv4 servers to significantly reduce the risk of exploitation.

Event History

Sep 9, 2020
CVE Published
12:00 AM
CVE Published
via MITRE·03:52 PM
Data Sourced
via MITRE·03:52 PM
Description
Data Sourced
via NVD·04:15 PM
RemedyDescriptionSeverityWeaknessAffected Software
Data Sourced
via Red Hat·08:57 PM
DescriptionSeverityAffected Software
Jan 11, 2024
Data Sourced
via Launchpad·11:46 PM
Description
Aug 12, 2026
Data Sourced
via Debian·04:18 PM
DescriptionAffected Software
Aug 14, 2026
Data Sourced
via Ubuntu·04:18 PM
RemedyDescriptionSeverityAffected Software

Parent advisories

This vulnerability appears in the following advisories.

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Frequently Asked Questions

1

What is the severity of CVE-2020-25212?

CVE-2020-25212 has a high severity rating due to the potential for memory corruption and privilege escalation.

2

How do I fix CVE-2020-25212?

To fix CVE-2020-25212, update to the latest kernel versions provided in the remediation section for your specific distribution.

3

Which software is affected by CVE-2020-25212?

CVE-2020-25212 affects various versions of the Linux kernel, particularly those prior to version 5.8.3.

4

Can CVE-2020-25212 lead to a security risk?

Yes, CVE-2020-25212 can lead to significant security risks including unauthorized privilege escalation.

5

Is CVE-2020-25212 a remote attack vulnerability?

Yes, CVE-2020-25212 can be exploited by a remote attacker through specially crafted NFS requests.

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