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CVE-2023-40547

HIGH severity · CVSS 8.3 · Out-of-bounds write
8.3CVSS HIGH

Summary

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.

Impact & exploitability

Attack vectorAdjacent
Attack complexityHigh
Privileges requiredNone
User interactionNone
Confidentiality impactHigh
Integrity impactHigh
Availability impactHigh
Exploit probability (EPSS)5%

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

Affected products we track (1)

Red Hat Enterprise Linux

Recommendation

Apply the vendor fix promptly. Open any affected product above for its exact safe version.

Additional information