exim4 — security advisory
Exim SMTP Challenge Stack-based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of Exim. Authentication is not required to exploit this vulnerability. The specific flaw exists within the handling of NTLM challenge requests. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of the service account. . Was ZDI-CAN-17515.
- Products
- exim4
- Affected versions
- 4.96-15, 4.96-15+deb12u1
- Fixed versions
- 4.96-15+deb12u2, 4.97~RC1-2
- CVEs
- CVE-2023-42116
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 16:25 UTC · Revision 1
Source evidence
Exim SMTP Challenge Stack-based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of Exim. Authentication is not required to exploit this vulnerability. The specific flaw exists within the handling of NTLM challenge requests. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of the service account. . Was ZDI-CAN-17515.
osv:DEBIAN-CVE-2023-42116
exim4
Fixed versions: 4.96-15+deb12u2
exim4
Fixed versions: 4.97~RC1-2
exim4
Fixed versions: 4.97~RC1-2
Complete source record
{
"id": "9fb51575a28e49417d551654203e864a15d379ebafbbdb07301bec7e36fe3bc4",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2023-42116",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2023-42116",
"summary": "Exim SMTP Challenge Stack-based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of Exim. Authentication is not required to exploit this vulnerability. The specific flaw exists within the handling of NTLM challenge requests. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of the service account. . Was ZDI-CAN-17515.",
"evidence": "osv:DEBIAN-CVE-2023-42116",
"products": [
{
"name": {
"value": "exim4",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "4.96-15+deb12u2",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": [
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"evidence": "/affected/0/versions"
},
{
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"evidence": "/affected/0/versions"
}
]
},
{
"name": {
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"evidence": "/affected/1/ranges"
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{
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"severity": "critical",
"structured": {
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"aliases": [
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"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
}
],
"affected": [
{
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"events": [
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],
"package": {
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"purl": "pkg:deb/debian/exim4?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
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"4.96-15+deb12u1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2023-42116.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
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{
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],
"package": {
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"purl": "pkg:deb/debian/exim4?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2023-42116.json"
},
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{
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{
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"package": {
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"purl": "pkg:deb/debian/exim4?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2023-42116.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-26T18:03:06.954140273Z",
"provider": "osv",
"upstream": [
"CVE-2023-42116"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2023-42116"
]
},
"related_cves": [
{
"value": "CVE-2023-42116",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 457691,
"published_at": "2024-05-03T03:15:50.303+00:00"
}