Severity
8.3HIGHNVD
EPSS
4.2%
top 11.29%
CISA KEV
Not in KEV
Exploit
No known exploits
Timeline
PublishedJan 25
Latest updateAug 13

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 success

CVSS vector

CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:HExploitability: 1.6 | Impact: 6.0

Affected Packages2 packages

NVDredhat/shim< 15.8
Debianredhat/shim< 15.8-1~deb11u1+3

Also affects: Enterprise Linux 7.0, 8.0, 9.0

🔴Vulnerability Details

3
OSV
CVE-2023-40547: A remote code execution vulnerability was found in Shim2024-01-25
GHSA
GHSA-qjqj-4cq6-6f2f: A remote code execution vulnerability was found in Shim2024-01-25
CVEList
Shim: rce in http boot support may lead to secure boot bypass2024-01-25

📋Vendor Advisories

3
Microsoft
Redhat: CVE-2023-40547 Shim - RCE in HTTP boot support may lead to secure boot bypass2024-08-13
Red Hat
shim: RCE in http boot support may lead to Secure Boot bypass2024-01-23
Debian
CVE-2023-40547: shim - A remote code execution vulnerability was found in Shim. The Shim boot support t...2023

🕵️Threat Intelligence

1
Bleepingcomputer
Critical flaw in Shim bootloader impacts major Linux distros2024-02-07