HOMEVULNERABILITIESCVE-2020-27749
MEDIUM

CVE-2020-27749

CWE-121Published: March 3, 2021· Updated: Jun 17, 2026

6.7
CVSS v3.1

Official Description

A flaw was found in grub2 in versions prior to 2.06. Variable names present are expanded in the supplied command line into their corresponding variable contents, using a 1kB stack buffer for temporary storage, without sufficient bounds checking. If the function is called with a command line that references a variable with a sufficiently large payload, it is possible to overflow the stack buffer, corrupt the stack frame and control execution which could also circumvent Secure Boot protections. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

NVD Source

Technical Analysis

CVE-2020-27749 requires local access, meaning attackers must already have a foothold on the target system.

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

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 6.7.

CVSS v3.1 Vector Breakdown

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

Affected Vendors & Products

Fedora1 product(s)
fedora
gnu1 product(s)
grub2
netapp1 product(s)
ontap select deploy administration utility
Red Hat5 product(s)
enterprise linuxenterprise linux server ausenterprise linux server eusenterprise linux server tusenterprise linux workstation
Source: NVD CPE · 20 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=1899966
PATCHhttps://bugzilla.redhat.com/show_bug.cgi?id=1899966
ADVISORYhttps://security.gentoo.org/glsa/202104-05
ADVISORYhttps://security.netapp.com/advisory/ntap-20220325-0001/
ADVISORYhttps://security.gentoo.org/glsa/202104-05
ADVISORYhttps://security.netapp.com/advisory/ntap-20220325-0001/

All References (8)

→
https://bugzilla.redhat.com/show_bug.cgi?id=1899966Issue Tracking · Patch · Third Party Advisory
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZWZ36QK4IKU6MWDWNOOWKPH3WXZBHT2R/
→
https://security.gentoo.org/glsa/202104-05Third Party Advisory
→
https://security.netapp.com/advisory/ntap-20220325-0001/Third Party Advisory
→
https://bugzilla.redhat.com/show_bug.cgi?id=1899966Issue Tracking · Patch · Third Party Advisory
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZWZ36QK4IKU6MWDWNOOWKPH3WXZBHT2R/
→
https://security.gentoo.org/glsa/202104-05Third Party Advisory
→
https://security.netapp.com/advisory/ntap-20220325-0001/Third Party Advisory

Quick Facts

CVE IDCVE-2020-27749
CVSS Score6.7 / 10
SeverityMEDIUM
WeaknessCWE-121
CISA KEVNo
Affected4 vendor(s)
PublishedMar 3, 2021

Related CVEs (CWE-121)

CVE-2026-37541
10.0
CVE-2021-21961
10.0
CVE-2020-14498
10.0
CVE-2026-12846
10.0
CVE-2021-21960
10.0
CVE-2026-42996
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2020-27749 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.
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