CVE-2023-40547

Highest-risk unexploited with PoCs

Exploit code exists, no confirmed in-the-wild activity, ranked by EPSS

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CVSS 8.3EPSS 5%

Published 2024-01-25Updated 2025-04-27

Media 6461

Vulnerability details

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.

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

CNAredhat

EPSS score history

Sources

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