CVE-2023-40547
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.
Key facts
- CVSS score
- 8.3 (v3.1)
- Severity
- HIGH
- CVSS vector
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H- Weakness (CWE)
- CWE-787
- EPSS score
- 5.4% (93th percentile)
- In CISA KEV
- No
- In EU EUVD
- Yes (EUVD-2023-45118)
- Published
- January 25, 2024
- NVD last modified
- June 26, 2026
- Status
- Modified
EU Vulnerability Database (EUVD)
This vulnerability is also tracked by ENISA as EUVD-2023-45118 in the EU Vulnerability Database. Last updated in EUVD on June 26, 2026.
View on the EU Vulnerability DatabaseAffected products
- redhat / enterprise linux
- redhat / enterprise linux
- redhat / enterprise linux
- redhat / shim
Certified products that may be affected
31 FIPS 140 or Common Criteria certified products, from automated matching by sec-certs.org.
- Red Hat Enterprise Linux 8 NSS Cryptographic Module - Red Hat, Inc. - FIPS 140 5513 - active
- Red Hat Enterprise Linux 8 Kernel Cryptographic API - Red Hat, LLC - FIPS 140 5461 - active
- Red Hat Enterprise Linux 9 Kernel Cryptographic API - Red Hat, Inc. - FIPS 140 5445 - active
- Red Hat Enterprise Linux 9 libgcrypt - Red Hat, Inc. - FIPS 140 5366 - active
- Red Hat Enterprise Linux 8 Kernel Cryptographic API - Red Hat, Inc. - FIPS 140 5089 - active
See all 31 in the Security Certifications Explorer.
References
- http://www.openwall.com/lists/oss-security/2024/01/26/1
- https://access.redhat.com/errata/RHSA-2024:1834
- https://access.redhat.com/errata/RHSA-2024:1835
- https://access.redhat.com/errata/RHSA-2024:1873
- https://access.redhat.com/errata/RHSA-2024:1876
- https://access.redhat.com/errata/RHSA-2024:1883
- https://access.redhat.com/errata/RHSA-2024:1902
- https://access.redhat.com/errata/RHSA-2024:1903
- https://access.redhat.com/errata/RHSA-2024:1959
- https://access.redhat.com/errata/RHSA-2024:2086
- https://access.redhat.com/security/cve/CVE-2023-40547(Vendor Advisory)
- https://bugzilla.redhat.com/show_bug.cgi?id=2234589(Issue Tracking, Vendor Advisory)
- https://lists.debian.org/debian-lts-announce/2024/05/msg00009.html
Last updated September 17, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS
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