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.

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Advisories
Source ID Title
Debian DLA Debian DLA DLA-3813-1 shim security update
EUVD EUVD EUVD-2023-45118 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.
Fixes

Solution

No solution given by the vendor.


Workaround

If a system isn’t required to boot from the network, configure the server’s boot order to disable entirely or skip the network boot.

History

Tue, 17 Jun 2025 22:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Fri, 22 Nov 2024 12:00:00 +0000


Mon, 16 Sep 2024 19:45:00 +0000


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2025-11-20T07:24:31.172Z

Reserved: 2023-08-15T20:04:15.615Z

Link: CVE-2023-40547

cve-icon Vulnrichment

Updated: 2024-08-02T18:38:50.942Z

cve-icon NVD

Status : Modified

Published: 2024-01-25T16:15:07.717

Modified: 2024-11-21T08:19:41.650

Link: CVE-2023-40547

cve-icon Redhat

Severity : Important

Publid Date: 2024-01-23T00:00:00Z

Links: CVE-2023-40547 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses