{"cve":"CVE-2023-40547","nvd":{"published":"2024-01-25T16:15:07.717","modified":"2026-06-26T10:16:21.907","status":"Modified","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H","score":8.3},"cwes":["CWE-787","CWE-346"],"references":["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"],"products":["redhat:enterprise_linux","redhat:shim"],"source":"nvd","synced_at":"2026-10-19T21:44:57.175229480+00:00"},"epss":{"cve":"CVE-2023-40547","score":0.05417,"percentile":0.92698,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}