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CVE-2023-40551

18
FAUCET Score

CVE-2023-40551 is an out-of-bounds read vulnerability in the Shim MZ binary format, affecting various Fedora and Red Hat Enterprise Linux products. This flaw, with a CVSS score of 5.1 (MEDIUM), could lead to system crashes or sensitive data exposure during the boot phase, requiring high privileges for exploitation. There is currently no evidence of active exploitation, public exploit code, or significant community discussion surrounding this vulnerability. Its EPSS score is very low, indicating a minimal probability of exploitation.

Impacted Technologies

VendorProductVersion(s)CPE
< 15.8CPE matchmatch criteria
cpe:2.3:a:redhat:shim:*:*:*:*:*:*:*:*
39CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:39:*:*:*:*:*:*:*
8.0CPE matchmatch criteria
cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
9.0CPE matchmatch criteria
cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

5.1MEDIUM

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

Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
HIGH
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
LOW
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
0.8
Impact Score
4.2
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.39%
Probability of exploitation in next 30 days
EPSS Percentile
32.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-25
Model: v2026.06.15
This CVE's current EPSS score of 0.0039 is in the 81st percentile among its peer group of 3,720 CVEs.

Social Chatter

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

Media Mentions

No media coverage found for this CVE.

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

Remediation

Patch Available

Vendor Patches (31)

microsoftpatch availablevia msrc
Product: azl3 shim 15.4-2 on Azure Linux 3.0Fixed in: 15.8-5
microsoftpatch availablevia msrc
Product: azl3 shim 15.8-5 on Azure Linux 3.0Fixed in: 15.8-5
microsoftpatch availablevia msrc
Product: 18174-16823Fixed in: 15.8-1
microsoftpatch availablevia msrc
Product: 19883-17086Fixed in: 15.8-1
microsoftpatch availablevia msrc
Product: 18175-17084Fixed in: 15.8-5
microsoftpatch availablevia msrc
Product: 19885-17084Fixed in: 15.8-5
microsoftpatch availablevia msrc
Product: Azure Linux 3.0 x64Fixed in: 15.8-3
microsoftpatch availablevia msrc
Product: CBL Mariner 2.0 x64Fixed in: 15.8-1
microsoftpatch availablevia msrc
Product: CBL Mariner 2.0 ARMFixed in: 15.8-1
microsoftpatch availablevia msrc
Product: Azure Linux 3.0 ARMFixed in: 15.8-3
microsoftpatch availablevia msrc
Product: cbl2 shim 15.8-1 on CBL Mariner 2.0Fixed in: 15.8-1
microsoftpatch availablevia msrc
Product: cbl2 shim 15.4-2 on CBL Mariner 2.0Fixed in: 15.8-1
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.8 Extended Update SupportFixed in: shim-unsigned-x64-0:15.8-2.el8
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 9Fixed in: shim-0:15.8-4.el9_3
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 9.0 Extended Update SupportFixed in: shim-0:15.8-3.el9
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 9.0 Extended Update SupportFixed in: shim-unsigned-x64-0:15.8-2.el9
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 9.2 Extended Update SupportFixed in: shim-0:15.8-3.el9_2
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 9.0 Extended Update SupportFixed in: shim-unsigned-aarch64-0:15.8-2.el9
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: shim-0:15.8-3.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: shim-signed-0:15.8-1.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: shim-0:15.8-4.el8_9
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.2 Advanced Update SupportFixed in: shim-0:15.8-2.el8_2
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.2 Telecommunications Update ServiceFixed in: shim-0:15.8-2.el8_2
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.2 Update Services for SAP SolutionsFixed in: shim-0:15.8-2.el8_2
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update SupportFixed in: shim-0:15.8-2.el8_4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.4 Telecommunications Update ServiceFixed in: shim-0:15.8-2.el8_4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.4 Update Services for SAP SolutionsFixed in: shim-0:15.8-2.el8_4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.6 Extended Update SupportFixed in: shim-0:15.8-2.el8_6
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.8 Extended Update SupportFixed in: shim-0:15.8-2.el8
View patch
grafanavendor investigatingvia llm_extracted
View patch
redhatvendor investigatingvia nvd_reference
View patch

Vendor Advisories (4)

grafanallm-grafana-3bfe68bd8f94bc6dCRITICAL

HP ThinPro 8.1 SP9 Security Updates

Feb 2, 2026
microsoft2024-Dec/CVE-2023-40551

CVE-2023-40551

Dec 10, 2024
redhatCVE-2023-40551Moderate

shim: out of bounds read when parsing MZ binaries

Jan 23, 2024
microsoft2024-Jan/CVE-2023-40551Moderate

Shim: out of bounds read when parsing mz binaries

Jan 9, 2024

References

lists.debian.org / debian-lts-announce/2024/05/msg00009.html
access.redhat.com / errata/RHSA-2024:1834
access.redhat.com / errata/RHSA-2024:1835
access.redhat.com / errata/RHSA-2024:1873
access.redhat.com / errata/RHSA-2024:1876
access.redhat.com / errata/RHSA-2024:1883
access.redhat.com / errata/RHSA-2024:1902
access.redhat.com / errata/RHSA-2024:1903
access.redhat.com / errata/RHSA-2024:1959
access.redhat.com / errata/RHSA-2024:2086
access.redhat.com / security/cve/CVE-2023-40551
Vendor Advisory
bugzilla.redhat.com / show_bug.cgi
Issue TrackingVendor Advisory