CVE-2020-9391

Name: CVE-2020-9391
Creator: NVD / NIST
Published: 2020-02-25T18:15:11.647+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.5/10EPSS 0.50%

Last modified Jun 17, 2026

CVE-2020-9391 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. An issue was discovered in the Linux kernel 5.4 and 5.5 through 5.5.6 on the AArch64 architecture. It ignores the top byte in the address passed to the brk system call, potentially moving the memory break downwards when the application expects it to move upwards, aka CID-dcde237319e6. EPSS estimates a 0.50% chance of exploitation in the next 30 days.

Description

An issue was discovered in the Linux kernel 5.4 and 5.5 through 5.5.6 on the AArch64 architecture. It ignores the top byte in the address passed to the brk system call, potentially moving the memory break downwards when the application expects it to move upwards, aka CID-dcde237319e6. This has been observed to cause heap corruption with the GNU C Library malloc implementation.

Metrics

CVSS 3.1

5.5/10

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

EPSS Probability

0.50%

38.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-787

Affected Software

Vendor	Product	Versions
Linux	Linux Kernel	>= 5.5, <= 5.5.6
Linux	Linux Kernel	5.4
Fedoraproject	Fedora	31
Netapp	Active Iq Unified Manager	All versions
Netapp	Cloud Backup	All versions
Netapp	Data Availability Services	All versions
Netapp	Hci Management Node	All versions
Netapp	Solidfire	All versions
Netapp	Steelstore Cloud Integrated Storage	All versions
Netapp	H410c Firmware	All versions

References

http://www.openwall.com/lists/oss-security/2020/02/25/6Exploit, Mailing List, Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1797052Exploit, Issue Tracking, Patch, Third Party Advisory
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=dcde237319e626d1ec3c9d8b7613032f0fd4663aMailing List, Patch, Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/O4LH35HOPBJIKYHYFXMBBM75DN75PZHZ/
https://security.netapp.com/advisory/ntap-20200313-0003/Third Party Advisory
http://www.openwall.com/lists/oss-security/2020/02/25/6Exploit, Mailing List, Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1797052Exploit, Issue Tracking, Patch, Third Party Advisory
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=dcde237319e626d1ec3c9d8b7613032f0fd4663aMailing List, Patch, Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/O4LH35HOPBJIKYHYFXMBBM75DN75PZHZ/
https://security.netapp.com/advisory/ntap-20200313-0003/Third Party Advisory

Timeline

Published: Feb 25, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-9391?

How severe is CVE-2020-9391?

CVE-2020-9391 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.50% probability of exploitation in the next 30 days.

How do I fix CVE-2020-9391?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-9391?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST