Exploitation evidence
Known exploited · CISA KEV listed
Added 2026-05-20. Ransomware campaign use: Unknown.
CISA required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
CISA due date: 2026-06-03. This is the catalog’s deadline, not an assessment of your organization’s exposure.
KEV checked 13 Nov 2026, 00:20 Jerusalem · Original catalog ↗Reported products and versions
Microsoft / Microsoft Malware Protection Engine
Default status: Not specified
- affected: 1.1.0.0 to < 1.1.26040.8 (custom)
Fixes and workarounds
No explicit solution text in the downloaded CVE record. Consult the vendor advisory; unaffected version ranges are shown above as reported, not inferred as a patch recommendation.
Sources and related reporting
Observed change timeline
History begins when Egret first downloads each source. It is not the complete upstream CVE history.
12 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-12",
"epss": 0.08202,
"percentile": 0.94955
}10 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-10",
"epss": 0.08202,
"percentile": 0.94922
}09 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-09",
"epss": 0.08202,
"percentile": 0.94916
}08 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-08",
"epss": 0.08202,
"percentile": 0.94913
}07 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-07",
"epss": 0.08202,
"percentile": 0.94911
}06 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-06",
"epss": 0.08202,
"percentile": 0.94902
}06 Nov 2026, 06:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-05",
"epss": 0.08202,
"percentile": 0.94897
}04 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-04",
"epss": 0.08202,
"percentile": 0.94893
}03 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-03",
"epss": 0.08202,
"percentile": 0.94885
}03 Nov 2026, 12:20 Jerusalem · CVE Program record changed
Stored CNA snapshot at this observation.
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-41091",
"options": [
{
"Exploitation": "active"
},
{
"Automatable": "no"
},
{
"Technical Impact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-05-20T00:00:00+00:00",
"version": "2.0.3"
},
"type": "ssvc"
}
},
{
"other": {
"content": {
"dateAdded": "2026-05-20",
"reference": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-41091"
},
"type": "kev"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-05-21T03:55:23.197Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"references": [
{
"tags": [
"government-resource"
],
"url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-41091"
}
],
"timeline": [
{
"lang": "en",
"time": "2026-05-20T00:00:00.000Z",
"value": "CVE-2026-41091 added to CISA KEV"
}
],
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"product": "Microsoft Malware Protection Engine",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "1.1.26040.8",
"status": "affected",
"version": "1.1.0.0",
"versionType": "custom"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:a:microsoft:malware_protection_engine:*:*:*:*:*:*:*:*",
"versionEndExcluding": "1.1.26040.8",
"versionStartIncluding": "1.1.0.0",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"datePublic": "2026-05-19T14:00:00.000Z",
"descriptions": [
{
"lang": "en-US",
"value": "Improper link resolution before file access ('link following') in Microsoft Defender allows an authorized attacker to elevate privileges locally."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C",
"version": "3.1"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en-US",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-59",
"description": "CWE-59: Improper Link Resolution Before File Access ('Link Following')",
"lang": "en-US",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-10T15:13:49.938Z",
"orgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8",
"shortName": "microsoft"
},
"references": [
{
"name": "Microsoft Defender Elevation of Privilege Vulnerability",
"tags": [
"vendor-advisory",
"patch"
],
"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-41091"
}
],
"title": "Microsoft Defender Elevation of Privilege Vulnerability"
}
},
"cveMetadata": {
"assignerOrgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8",
"assignerShortName": "microsoft",
"cveId": "CVE-2026-41091",
"datePublished": "2026-05-20T13:09:13.634Z",
"dateReserved": "2026-04-16T19:12:36.195Z",
"dateUpdated": "2026-08-10T15:13:49.938Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}03 Nov 2026, 02:22 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-02",
"epss": 0.08202,
"percentile": 0.94878
}03 Nov 2026, 02:22 Jerusalem · CISA KEV status changed
Stored KEV snapshot at this observation.
{
"cveID": "CVE-2026-41091",
"cwes": [
"CWE-59"
],
"dateAdded": "2026-05-20",
"dueDate": "2026-06-03",
"forensicTriage": "No",
"knownRansomwareCampaignUse": "Unknown",
"notes": "https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-41091 ; https://nvd.nist.gov/vuln/detail/CVE-2026-41091",
"product": "Defender",
"requiredAction": "Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.",
"shortDescription": "Microsoft Defender contains a link following vulnerability that allows an authorized attacker to elevate privileges locally.",
"vendorProject": "Microsoft",
"vulnerabilityName": "Microsoft Defender Link Following Vulnerability"
}