Is CVE-2021-3697 in the CISA KEV catalog?

No. CVE-2021-3697 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-3697?

CVE-2021-3697 has a CVSS v3 base score of 7.0 (HIGH).

What is the EPSS score for CVE-2021-3697?

CVE-2021-3697 has an EPSS score of 0.46% (36th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-3697?

Upgrade grub2 on debian 11 to 2.06-3~deb11u1 or later. Fixes are available for 11 affected products.

CVE & CISA-KEV Catalog

CVE-2021-3697

HIGH

7.0

CVSS v3

NVD

Description

A crafted JPEG image may lead the JPEG reader to underflow its data pointer, allowing user-controlled data to be written in heap. To a successful to be performed the attacker needs to perform some triage over the heap layout and craft an image with a malicious format and payload. This vulnerability can lead to data corruption and eventual code execution or secure boot circumvention. This flaw affects grub2 versions prior grub-2.12.

CWE-787Out-of-bounds Write

How to fix

Remediation Available

grub2Debian

Fixed in:2.06-3~deb11u1CVE-2021-3697

Fixed in:2.06-3CVE-2021-3697

grub-efi-amd64Ubuntu

Fixed in:2.06-2ubuntu14.1USN-6355-1

grub-efi-amd64-binUbuntu

Fixed in:2.06-2ubuntu14.1USN-6355-1

grub-efi-amd64-signedUbuntu

Fixed in:1.187.3~20.04.1+2.06-2ubuntu14.1USN-6355-1

Fixed in:1.187.3~22.04.1+2.06-2ubuntu14.1USN-6355-1

grub-efi-arm64Ubuntu

Fixed in:2.06-2ubuntu14.1USN-6355-1

grub-efi-arm64-binUbuntu

Fixed in:2.06-2ubuntu14.1USN-6355-1

grub-efi-arm64-signedUbuntu

Fixed in:1.187.3~20.04.1+2.06-2ubuntu14.1USN-6355-1

Fixed in:1.187.3~22.04.1+2.06-2ubuntu14.1USN-6355-1

grub2-signedUbuntu

Fixed in:1.187.3~20.04.1USN-6355-1

Fixed in:1.187.3~22.04.1USN-6355-1

grub2-unsignedUbuntu

Fixed in:2.06-2ubuntu14.1USN-6355-1

shimUbuntu

Fixed in:15.7-0ubuntu1USN-6355-1

shim-signedUbuntu

Fixed in:1.40.9USN-6355-1

Fixed in:1.51.3USN-6355-1

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 ComplexityHigh

Privileges RequiredLow

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

0.46%probability of exploitation in 30 days

36thpercentile

Low risk: more likely to be exploited than 36% of all known CVEs.

References

Third-Party Advisory3

Related Vulnerabilities

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

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2025-22457	Critical	9.0	100%	KEV + Ransom	Fix
CVE-2025-0282	Critical	9.0	100%	KEV + Ransom	-
CVE-2015-3113	Critical	9.8	100%	KEV	Fix
CVE-2021-20038	Critical	9.8	100%	KEV + Ransom	-
CVE-2023-4863	High	8.8	100%	KEV	Fix
CVE-2020-16040	Medium	6.5	100%	-	Fix

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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.