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redhatcveRedhat.comRH:CVE-2023-40547
HistoryJan 24, 2024 - 1:48 p.m.

CVE-2023-40547

2024-01-2413:48:11
redhat.com
access.redhat.com
42
remote code execution
vulnerability
shim boot
http response parsing
out-of-bounds write
system compromise
early boot phase
man-in-the-middle
boot server compromise
mitigation

8.3 High

CVSS3

Attack Vector

ADJACENT

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction

NONE

Scope

CHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

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

9.6 High

AI Score

Confidence

High

0.025 Low

EPSS

Percentile

90.3%

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.

Mitigation

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.

8.3 High

CVSS3

Attack Vector

ADJACENT

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction

NONE

Scope

CHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

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

9.6 High

AI Score

Confidence

High

0.025 Low

EPSS

Percentile

90.3%