CVE-2023-40547: redhat enterprise_linux Out-of-bounds Write

Vulnerability summary

CVE-2023-40547 is a high (CVSS 8.3) Out-of-bounds Write vulnerability in redhat enterprise_linux. EPSS estimates a 5.42% chance of exploitation in the next 30 days, higher than 92.6% of scored vulnerabilities.

Timeline

1. 25-01-2024
   PublishedVulnerability first disclosed.
2. 26-06-2026
   Last modifiedVulnerability information updated.

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 successfully.

• CWE-787Out-of-bounds WriteThe product writes data past the end, or before the beginning, of the intended buffer.
• CWE-346Origin Validation ErrorThe product does not properly verify that the source of data or communication is valid.