HOMEVULNERABILITIESCVE-2020-9391
MEDIUM

CVE-2020-9391

CWE-787Published: February 25, 2020· Updated: Jun 17, 2026

5.5
CVSS v3.1

Official 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.

NVD Source

Technical Analysis

CVE-2020-9391 requires local access, meaning attackers must already have a foothold on the target system.

Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 5.5.

From a weakness classification perspective (CWE-787): Out-of-bounds write vulnerabilities can lead to data corruption, crashes, or arbitrary code execution.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorLocal
Attack ComplexityLow
Privileges Req.Low
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected Vendors & Products

Fedora1 product(s)
fedora
Linux1 product(s)
linux kernel
netapp8 product(s)
active iq unified managercloud backupdata availability serviceshci management nodesolidfiresteelstore cloud integrated storageh410c firmwareh410c
Source: NVD CPE · 11 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://bugzilla.redhat.com/show_bug.cgi?id=1797052
PATCHhttps://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=dcde237319e626d1ec3c9d8b7613032f0fd4663a
PATCHhttps://bugzilla.redhat.com/show_bug.cgi?id=1797052
PATCHhttps://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=dcde237319e626d1ec3c9d8b7613032f0fd4663a
ADVISORYhttp://www.openwall.com/lists/oss-security/2020/02/25/6
ADVISORYhttps://security.netapp.com/advisory/ntap-20200313-0003/
ADVISORYhttp://www.openwall.com/lists/oss-security/2020/02/25/6
ADVISORYhttps://security.netapp.com/advisory/ntap-20200313-0003/

All References (10)

→
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

Quick Facts

CVE IDCVE-2020-9391
CVSS Score5.5 / 10
SeverityMEDIUM
WeaknessCWE-787
CISA KEVNo
Affected3 vendor(s)
PublishedFeb 25, 2020

Related CVEs (CWE-787)

CVE-2019-6235
10.0
CVE-2009-2466
10.0
CVE-2018-6692
10.0
CVE-2018-17160
10.0
CVE-2020-11897
10.0
CVE-2026-42369
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2020-9391 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.
← All Vulnerabilities·Search for CVE-2020-9391·NVD