Shim: rce in http boot support may lead to secure boot bypass
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.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2023-40547
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 7 Nov 2026, 01:47 UTC · Revision 1
Source evidence
Shim: rce in http boot support may lead to secure boot bypass
core-osv · Original sourcePublished 25 Jan 2024, 15:54 UTC
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.
osv:CVE-2023-40547
Complete source record
{
"id": "c2a54b82e6d095878ba5c2c8736449dee5dffa5684f1274e338891d3b8cc438d",
"url": "https://osv.dev/vulnerability/CVE-2023-40547",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "Shim: rce in http boot support may lead to secure boot bypass",
"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.",
"evidence": "osv:CVE-2023-40547",
"products": [],
"severity": "high",
"structured": {
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"aliases": [
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"metrics": [
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"score": "CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H"
}
],
"affected": [
{
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"type": "GIT",
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"modified": "2026-10-28T02:30:48.659465174Z",
"provider": "osv",
"references": [
"https://access.redhat.com/downloads/content/package-browser/",
"https://lists.debian.org/debian-lts-announce/2024/05/msg00009.html",
"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",
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/40xxx/CVE-2023-40547.json",
"https://nvd.nist.gov/vuln/detail/CVE-2023-40547",
"https://bugzilla.redhat.com/show_bug.cgi?id=2234589"
],
"provider_metadata": {
"cwe_ids": [
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],
"cna_assigner": "redhat",
"unresolved_ranges": [
{
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"range": [
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"fixed": "0:15.8-3.el7"
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{
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{
"fixed": "0:15.8-4.el8_9"
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{
"fixed": "0:15.8-2.el8_2"
},
{
"fixed": "0:15.8-2.el8_2"
},
{
"fixed": "0:15.8-2.el8_2"
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{
"fixed": "0:15.8-2.el8_4"
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{
"fixed": "0:15.8-2.el8_4"
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{
"fixed": "0:15.8-2.el8_4"
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{
"fixed": "0:15.8-2.el8_6"
},
{
"fixed": "0:15.8-2.el8"
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{
"fixed": "0:15.8-2.el8"
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{
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{
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{
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{
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},
{
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}
],
"source": "AFFECTED_FIELD",
"strategy": "InverseAffectedRanges"
}
]
}
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/40xxx/CVE-2023-40547.json"
}
},
"related_cves": [
{
"value": "CVE-2023-40547",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 517096,
"published_at": "2024-01-25T15:54:23.102+00:00"
}