CVE-2023-40547
Shim: rce in http boot support may lead to secure boot bypass
CVSS Score
8.3
EPSS Score
0.0%
EPSS Percentile
0th
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 | CWE-787 |
| Vendor | red hat |
| Product | red hat enterprise linux 7 |
| Published | Jan 25, 2024 |
| Last Updated | Nov 20, 2025 |
Stay Ahead of the Next One
Get instant alerts for red hat red hat enterprise linux 7
Be the first to know when new high vulnerabilities affecting red hat red hat enterprise linux 7 are published — delivered to Slack, Telegram or Discord.
Get Free Alerts →
Free · No credit card · 60 sec setup
CVSS v3 Breakdown
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H Attack Vector
Adjacent
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High
Affected Versions
Red Hat / Red Hat Enterprise Linux 7
All versions affected Red Hat / Red Hat Enterprise Linux 7
All versions affected Red Hat / Red Hat Enterprise Linux 8
All versions affected Red Hat / Red Hat Enterprise Linux 8.2 Advanced Update Support
All versions affected Red Hat / Red Hat Enterprise Linux 8.2 Telecommunications Update Service
All versions affected Red Hat / Red Hat Enterprise Linux 8.2 Update Services for SAP Solutions
All versions affected Red Hat / Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
All versions affected Red Hat / Red Hat Enterprise Linux 8.4 Telecommunications Update Service
All versions affected Red Hat / Red Hat Enterprise Linux 8.4 Update Services for SAP Solutions
All versions affected Red Hat / Red Hat Enterprise Linux 8.6 Extended Update Support
All versions affected Red Hat / Red Hat Enterprise Linux 8.8 Extended Update Support
All versions affected Red Hat / Red Hat Enterprise Linux 8.8 Extended Update Support
All versions affected Red Hat / Red Hat Enterprise Linux 9
All versions affected Red Hat / Red Hat Enterprise Linux 9.0 Extended Update Support
All versions affected Red Hat / Red Hat Enterprise Linux 9.0 Extended Update Support
All versions affected Red Hat / Red Hat Enterprise Linux 9.0 Extended Update Support
All versions affected Red Hat / Red Hat Enterprise Linux 9.2 Extended Update Support
All versions affected References
access.redhat.com: https://access.redhat.com/errata/RHSA-2024:1834 access.redhat.com: https://access.redhat.com/errata/RHSA-2024:1835 access.redhat.com: https://access.redhat.com/errata/RHSA-2024:1873 access.redhat.com: https://access.redhat.com/errata/RHSA-2024:1876 access.redhat.com: https://access.redhat.com/errata/RHSA-2024:1883 access.redhat.com: https://access.redhat.com/errata/RHSA-2024:1902 access.redhat.com: https://access.redhat.com/errata/RHSA-2024:1903 access.redhat.com: https://access.redhat.com/errata/RHSA-2024:1959 access.redhat.com: https://access.redhat.com/errata/RHSA-2024:2086 access.redhat.com: https://access.redhat.com/security/cve/CVE-2023-40547 bugzilla.redhat.com: https://bugzilla.redhat.com/show_bug.cgi?id=2234589 openwall.com: http://www.openwall.com/lists/oss-security/2024/01/26/1 lists.debian.org: https://lists.debian.org/debian-lts-announce/2024/05/msg00009.html
Credits
Red Hat would like to thank Bill Demirkapi (Microsoft Security Response Center) for reporting this issue.