CVE & CISA-KEV Catalog

CVE-2021-20225

MEDIUM
6.7
CVSS v3
NVD

Description

A flaw was found in grub2 in versions prior to 2.06. The option parser allows an attacker to write past the end of a heap-allocated buffer by calling certain commands with a large number of specific short forms of options. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

How to fix

Remediation Available
grub2Debian
Fixed in:2.04-16CVE-2021-20225
Fixed in:2.04-16CVE-2021-20225
Fixed in:2.04-16CVE-2021-20225
Fixed in:2.04-16CVE-2021-20225
grub-efi-amd64-binUbuntu
Fixed in:2.04-1ubuntu44.1.2USN-4992-1
Fixed in:2.04-1ubuntu44.2USN-4992-1
grub-efi-amd64-signedUbuntu
Fixed in:1.167~18.04.5+2.04-1ubuntu44.1.2USN-4992-1
Fixed in:1.167.2+2.04-1ubuntu44.2USN-4992-1
grub-efi-arm64-binUbuntu
Fixed in:2.04-1ubuntu44.1.2USN-4992-1
Fixed in:2.04-1ubuntu44.2USN-4992-1
grub-efi-arm64-signedUbuntu
Fixed in:1.167~18.04.5+2.04-1ubuntu44.1.2USN-4992-1
Fixed in:1.167.2+2.04-1ubuntu44.2USN-4992-1
grub2-signedUbuntu
Fixed in:1.167~18.04.5USN-4992-1
Fixed in:1.167.2USN-4992-1
grub2-unsignedUbuntu
Fixed in:2.04-1ubuntu44.1.2USN-4992-1
Fixed in:2.04-1ubuntu44.2USN-4992-1

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorLocal
Attack ComplexityLow
Privileges RequiredHigh
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

Exploit Intelligence

1.02%probability of exploitation in 30 days
59thpercentile

Moderate risk: more likely to be exploited than 59% of all known CVEs.

References

Related Vulnerabilities

Other CWE-787 (Out-of-bounds Write) vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2025-22457Critical9.0100%KEV + RansomFix
CVE-2025-0282Critical9.0100%KEV + Ransom-
CVE-2015-3113Critical9.8100%KEVFix
CVE-2021-20038Critical9.8100%KEV + Ransom-
CVE-2023-4863High8.8100%KEVFix
CVE-2020-16040Medium6.5100%-Fix
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CVE-2021-20225 severity badge

Markdown

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HTML

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.