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CVE-2023-40547

Shim: rce in http boot support may lead to secure boot bypass

Published: Jan 25, 2024Updated: Jun 26, 2026 Sources: CVE List NVD BDUCWE-787

Description

A remote code execution vulnerability was found in Shim. The Shim boot support trusts attacker-controlled values when parsing an HTTP response. This flaw allows an attacker to craft a specific malicious HTTP request, leading to a completely controlled out-of-bounds write primitive and complete system compromise. This flaw is only exploitable during the early boot phase, an attacker needs to perform a Man-in-the-Middle or compromise the boot server to be able to exploit this vulnerability successfully.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:AAC:HPR:NUI:NS:CC:HI:HA:H
Exploitability
AV:AAttack Vector
Adjacent
AC:HAttack Complexity
High
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:CScope
Changed
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:HAvailability
High

Weaknesses

Affected Products

and 9 more affected products View all →

Exploitability

Official Patch Available
Workaround Available

Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

2 techniques
Initial Access
Privilege Escalation
View detailed technique mapping

References

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1

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