shim — security advisory
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
- shim
- Affected versions
- 15.7-1, 15.8-1~deb10u1, 15.8-1~deb11u1
- Fixed versions
- 15.8-1, 15.8-1~deb12u1
- CVEs
- CVE-2023-40547
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 15:57 UTC · Revision 1
Source evidence
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:DEBIAN-CVE-2023-40547
shim
Fixed versions: 15.8-1~deb12u1
shim
Fixed versions: 15.8-1
shim
Fixed versions: 15.8-1
Complete source record
{
"id": "4310e6a5e127f2db7232e477273f74a1b6fab849bbf02bce63e3e3bba85b5e9c",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2023-40547",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2023-40547",
"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:DEBIAN-CVE-2023-40547",
"products": [
{
"name": {
"value": "shim",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "15.8-1~deb12u1",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": [
{
"value": "15.7-1",
"evidence": "/affected/0/versions"
},
{
"value": "15.8-1~deb10u1",
"evidence": "/affected/0/versions"
},
{
"value": "15.8-1~deb11u1",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "shim",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
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"evidence": "/affected/1/ranges"
}
],
"affected_versions": []
},
{
"name": {
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},
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],
"affected_versions": []
}
],
"severity": "high",
"structured": {
"id": "DEBIAN-CVE-2023-40547",
"aliases": [
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],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "15.8-1~deb12u1"
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}
],
"package": {
"name": "shim",
"purl": "pkg:deb/debian/shim?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"15.7-1",
"15.8-1~deb10u1",
"15.8-1~deb11u1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2023-40547.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
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},
{
"fixed": "15.8-1"
}
]
}
],
"package": {
"name": "shim",
"purl": "pkg:deb/debian/shim?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2023-40547.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
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},
{
"fixed": "15.8-1"
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],
"package": {
"name": "shim",
"purl": "pkg:deb/debian/shim?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2023-40547.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-26T18:02:32.214456470Z",
"provider": "osv",
"upstream": [
"CVE-2023-40547"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2023-40547"
]
},
"related_cves": [
{
"value": "CVE-2023-40547",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 456199,
"published_at": "2024-01-25T16:15:07.717+00:00"
}