Predictive Vulnerability Intelligence.

Product

  • Product
  • Pricing
  • Documentation

Company

  • About
  • Partnerships
  • Blog
  • Support

Legal

  • Terms
  • Privacy
  • Data Licensing

© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2021-3697

24
FAUCET Score

CVE-2021-3697 is a heap underflow vulnerability in grub2 versions prior to 2.12, affecting GNU and Red Hat products. A specially crafted JPEG image can cause the JPEG reader to underflow its data pointer, allowing an attacker to write user-controlled data to the heap. This high-severity flaw (CVSS 7.0) requires an attacker to manipulate the heap layout and craft a malicious image, potentially leading to data corruption, code execution, or secure boot circumvention. There is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage for this vulnerability.

Impacted Technologies

VendorProductVersion(s)CPE
>= 2.00, < 2.12CPE matchmatch criteria
cpe:2.3:a:gnu:grub2:*:*:*:*:*:*:*:*
1.0CPE matchmatch criteria
cpe:2.3:a:redhat:developer_tools:1.0:*:*:*:*:*:*:*
3.0CPE matchmatch criteria
cpe:2.3:a:redhat:openshift:3.0:*:*:*:*:*:*:*
8.0CPE matchmatch criteria
cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
8.1CPE matchmatch criteria
cpe:2.3:o:redhat:enterprise_linux:8.1:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.0HIGH

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

Attack Vector
LOCAL
Attack Complexity
HIGH
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
1.0
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.46%
Probability of exploitation in next 30 days
EPSS Percentile
37.2%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
This CVE's current EPSS score of 0.0046 is in the 77th percentile among its peer group of 1,516 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.4 InfoSec Media, 0.1 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (13)

microsoftpatch availablevia msrc
Product: 18842-17084Fixed in: 2.06-14
microsoftpatch availablevia msrc
Product: 19663-17084Fixed in: 2.06-14
microsoftpatch availablevia msrc
Product: azl3 grub2 2.06-23 on Azure Linux 3.0Fixed in: 2.06-14
microsoftpatch availablevia msrc
Product: Azure Linux 3.0 x64Fixed in: 2.06-14
microsoftpatch availablevia msrc
Product: Azure Linux 3.0 ARMFixed in: 2.06-14
microsoftpatch availablevia msrc
Product: CBL Mariner 2.0 x64Fixed in: 2.06-12
microsoftpatch availablevia msrc
Product: CBL Mariner 2.0 ARMFixed in: 2.06-12
microsoftpatch availablevia msrc
Product: azl3 grub2 2.06-14 on Azure Linux 3.0Fixed in: 2.06-14
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: grub2-1:2.02-123.el8_6.8
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.1 Update Services for SAP SolutionsFixed in: grub2-1:2.02-87.el8_1.10
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.2 Extended Update SupportFixed in: grub2-1:2.02-87.el8_2.10
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.4 Extended Update SupportFixed in: grub2-1:2.02-99.el8_4.9
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 9Fixed in: grub2-1:2.06-27.el9_0.7
View patch

Vendor Advisories (3)

microsoft2024-Jun/CVE-2021-3697

CVE-2021-3697

Jun 11, 2024
microsoft2022-Jul/CVE-2021-3697Important

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.

Jul 12, 2022
redhatCVE-2021-3697Moderate

grub2: Crafted JPEG image can lead to buffer underflow write in the heap

Jun 7, 2022

References

bugzilla.redhat.com / show_bug.cgi
Issue TrackingThird Party Advisory
security.gentoo.org / glsa/202209-12
Third Party Advisory
security.netapp.com / advisory/ntap-20220930-0001
Third Party Advisory