CVE-2021-43890 (GCVE-0-2021-43890)
Vulnerability from cvelistv5 – Published: 2021-12-15 14:15 – Updated: 2026-08-06 03:55- Spoofing
- CWE-noinfo Not enough information
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Microsoft | App Installer |
Affected:
1.0.0.0 , < publication
(custom)
cpe:2.3:a:microsoft:app_installer:*:*:*:*:*:*:*:* |
CISA
Known Exploited Vulnerability - GCVE BCP-07 Compliant
Exploited: Yes
Timestamps
Scope
Evidence
Type: Vendor Report
Signal: Successful Exploitation
Confidence: 80%
Source: cisa-kev
Details
| Cwes | |
|---|---|
| Feed | CISA Known Exploited Vulnerabilities Catalog |
| Product | Windows |
| Due Date | 2021-12-29 |
| Date Added | 2021-12-15 |
| Vendorproject | Microsoft |
| Vulnerabilityname | Microsoft Windows AppX Installer Spoofing Vulnerability |
| Knownransomwarecampaignuse | Known |
References
Previdian
Known Exploited Vulnerability - GCVE BCP-07 Compliant
Exploited: Yes
Timestamps
Scope
Evidence
Type: Public Report
Signal: Confirmed Compromise
Confidence: 70%
Source: kevintel
Details
| Feed | KEVIntel (kevintel.com) |
|---|---|
| Title | Windows AppX Installer Spoofing Vulnerability |
| Vendor | Microsoft |
| Product | App Installer |
| Added Date | 2021-12-15T00:00:00.000Z |
| Cvss Score | 7.1 |
| Epss Score | None |
| Cvss Severity | HIGH |
| Epss Percentile | None |
| Used In Malware | yes |
| Ahead Of Cisa Kev | None |
| Not Yet In Cisa Kev | False |
References
{
"containers": {
"adp": [
{
"providerMetadata": {
"dateUpdated": "2024-08-04T04:10:17.079Z",
"orgId": "af854a3a-2127-422b-91ae-364da2661108",
"shortName": "CVE"
},
"references": [
{
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43890"
},
{
"tags": [
"x_transferred"
],
"url": "https://www.bleepingcomputer.com/news/microsoft/microsoft-disables-msix-protocol-handler-abused-in-malware-attacks/"
},
{
"tags": [
"x_transferred"
],
"url": "https://thehackernews.com/2023/12/microsoft-disables-msix-app-installer.html"
},
{
"tags": [
"x_transferred"
],
"url": "https://www.microsoft.com/en-us/security/blog/2023/12/28/financially-motivated-threat-actors-misusing-app-installer/"
},
{
"tags": [
"x_transferred"
],
"url": "https://github.com/ChrisTitusTech/winutil/pull/26"
}
],
"title": "CVE Program Container"
},
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2021-43890",
"options": [
{
"Exploitation": "active"
},
{
"Automatable": "no"
},
{
"Technical Impact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2021-12-14T00:00:00+00:00",
"version": "2.0.3"
},
"type": "ssvc"
}
},
{
"other": {
"content": {
"dateAdded": "2021-12-15",
"reference": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-43890"
},
"type": "kev"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"description": "CWE-noinfo Not enough information",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-06T03:55:23.978Z",
"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-2021-43890"
}
],
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"cpes": [
"cpe:2.3:a:microsoft:app_installer:*:*:*:*:*:*:*:*"
],
"platforms": [
"Unknown"
],
"product": "App Installer",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "publication",
"status": "affected",
"version": "1.0.0.0",
"versionType": "custom"
}
]
}
],
"datePublic": "2021-12-14T08:00:00.000Z",
"descriptions": [
{
"lang": "en-US",
"value": "We have investigated reports of a spoofing vulnerability in AppX installer that affects Microsoft Windows. Microsoft is aware of attacks that attempt to exploit this vulnerability by using specially crafted packages that include the malware family known as Emotet/Trickbot/Bazaloader.\nAn attacker could craft a malicious attachment to be used in phishing campaigns. The attacker would then have to convince the user to open the specially crafted attachment. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.\nPlease see the Security Updates table for the link to the updated app. Alternatively you can download and install the Installer using the links provided in the FAQ section.\nPlease see the Mitigations and Workaround sections for important information about steps you can take to protect your system from this vulnerability.\nDecember 27 2023 Update:\nIn recent months, Microsoft Threat Intelligence has seen an increase in activity from threat actors leveraging social engineering and phishing techniques to target Windows OS users and utilizing the ms-appinstaller URI scheme.\nTo address this increase in activity, we have updated the App Installer to disable the ms-appinstaller protocol by default and recommend other potential mitigations."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.1,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:R/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": [
{
"description": "Spoofing",
"lang": "en-US",
"type": "Impact"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2024-05-29T14:44:37.753Z",
"orgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8",
"shortName": "microsoft"
},
"references": [
{
"tags": [
"x_refsource_MISC"
],
"url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43890"
},
{
"url": "https://www.bleepingcomputer.com/news/microsoft/microsoft-disables-msix-protocol-handler-abused-in-malware-attacks/"
},
{
"url": "https://thehackernews.com/2023/12/microsoft-disables-msix-app-installer.html"
},
{
"url": "https://www.microsoft.com/en-us/security/blog/2023/12/28/financially-motivated-threat-actors-misusing-app-installer/"
},
{
"url": "https://github.com/ChrisTitusTech/winutil/pull/26"
}
],
"title": "Windows AppX Installer Spoofing Vulnerability"
}
},
"cveMetadata": {
"assignerOrgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8",
"assignerShortName": "microsoft",
"cveId": "CVE-2021-43890",
"datePublished": "2021-12-15T14:15:35.000Z",
"dateReserved": "2021-11-16T00:00:00.000Z",
"dateUpdated": "2026-08-06T03:55:23.978Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"cisa_known_exploited": {
"cveID": "CVE-2021-43890",
"dateAdded": "2021-12-15",
"dueDate": "2021-12-29",
"forensicTriage": "No",
"knownRansomwareCampaignUse": "Known",
"notes": "https://nvd.nist.gov/vuln/detail/CVE-2021-43890",
"product": "Windows",
"requiredAction": "Apply updates per vendor instructions.",
"shortDescription": "Microsoft Windows AppX Installer contains a spoofing vulnerability which has a high impacts to confidentiality, integrity, and availability.",
"vendorProject": "Microsoft",
"vulnerabilityName": "Microsoft Windows AppX Installer Spoofing Vulnerability"
},
"epss": {
"cve": "CVE-2021-43890",
"date": "2026-09-17",
"epss": "0.10295",
"percentile": "0.95462"
},
"fkie_nvd": {
"cisaActionDue": "2021-12-29",
"cisaExploitAdd": "2021-12-15",
"cisaRequiredAction": "Apply updates per vendor instructions.",
"cisaVulnerabilityName": "Microsoft Windows AppX Installer Spoofing Vulnerability",
"configurations": "[{\"operator\": \"AND\", \"nodes\": [{\"operator\": \"OR\", \"negate\": false, \"cpeMatch\": [{\"vulnerable\": true, \"criteria\": \"cpe:2.3:a:microsoft:app_installer:*:*:*:*:*:*:*:*\", \"versionEndExcluding\": \"1.16\", \"matchCriteriaId\": \"F5F1F637-0D18-4CBE-A56B-DEA530ACC1B0\"}]}, {\"operator\": \"OR\", \"negate\": false, \"cpeMatch\": [{\"vulnerable\": false, \"criteria\": \"cpe:2.3:o:microsoft:windows_10_1809:-:*:*:*:*:*:*:*\", \"matchCriteriaId\": \"2E332666-2E03-468E-BC30-299816D6E8ED\"}, {\"vulnerable\": false, \"criteria\": \"cpe:2.3:o:microsoft:windows_10_1903:-:*:*:*:*:*:*:*\", \"matchCriteriaId\": \"A363CE8F-F399-4B6E-9E7D-349792F95DDB\"}, {\"vulnerable\": false, \"criteria\": \"cpe:2.3:o:microsoft:windows_10_1909:-:*:*:*:*:*:*:*\", \"matchCriteriaId\": \"A1B570A8-ED1A-46B6-B8AB-064445F8FC4C\"}, {\"vulnerable\": false, \"criteria\": \"cpe:2.3:o:microsoft:windows_10_2004:-:*:*:*:*:*:*:*\", \"matchCriteriaId\": \"D4DBE5B2-AE10-4251-BCDA-DC5EDEE6EE67\"}, {\"vulnerable\": false, \"criteria\": \"cpe:2.3:o:microsoft:windows_10_20h2:-:*:*:*:*:*:*:*\", \"matchCriteriaId\": \"6AFD13A6-A390-4400-9029-2F4058CA17E2\"}, {\"vulnerable\": false, \"criteria\": \"cpe:2.3:o:microsoft:windows_10_21h1:-:*:*:*:*:*:*:*\", \"matchCriteriaId\": \"B1FED4C9-B680-4F44-ADC0-AC43D6B5F184\"}, {\"vulnerable\": false, \"criteria\": \"cpe:2.3:o:microsoft:windows_10_21h2:-:*:*:*:*:*:*:*\", \"matchCriteriaId\": \"2F513002-D8C1-4D3A-9F79-4B52498F67E9\"}, {\"vulnerable\": false, \"criteria\": \"cpe:2.3:o:microsoft:windows_11_21h2:-:*:*:*:*:*:*:*\", \"matchCriteriaId\": \"BB4AE761-6FAC-4000-A63D-42CE3FAB8412\"}]}]}, {\"operator\": \"AND\", \"nodes\": [{\"operator\": \"OR\", \"negate\": false, \"cpeMatch\": [{\"vulnerable\": true, \"criteria\": \"cpe:2.3:a:microsoft:app_installer:*:*:*:*:*:*:*:*\", \"versionEndExcluding\": \"1.11\", \"matchCriteriaId\": \"62B0A730-2442-4C85-8CFA-098D4DADFF8C\"}]}, {\"operator\": \"OR\", \"negate\": false, \"cpeMatch\": [{\"vulnerable\": false, \"criteria\": \"cpe:2.3:o:microsoft:windows_10_1507:-:*:*:*:*:*:*:*\", \"matchCriteriaId\": \"542DAEEC-73CC-46C6-A630-BF474A3446AC\"}, {\"vulnerable\": false, \"criteria\": \"cpe:2.3:o:microsoft:windows_10_1709:-:*:*:*:*:*:*:*\", \"matchCriteriaId\": \"AC160B20-3EA0-49A0-A857-4E7A1C2D74E2\"}, {\"vulnerable\": false, \"criteria\": \"cpe:2.3:o:microsoft:windows_10_1803:-:*:*:*:*:*:*:*\", \"matchCriteriaId\": \"00345596-E9E0-4096-8DC6-0212F4747A13\"}]}]}]",
"descriptions": "[{\"lang\": \"en\", \"value\": \"We have investigated reports of a spoofing vulnerability in AppX installer that affects Microsoft Windows. Microsoft is aware of attacks that attempt to exploit this vulnerability by using specially crafted packages that include the malware family known as Emotet/Trickbot/Bazaloader.\\nAn attacker could craft a malicious attachment to be used in phishing campaigns. The attacker would then have to convince the user to open the specially crafted attachment. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.\\nPlease see the Security Updates table for the link to the updated app. Alternatively you can download and install the Installer using the links provided in the FAQ section.\\nPlease see the Mitigations and Workaround sections for important information about steps you can take to protect your system from this vulnerability.\\nDecember 27 2023 Update:\\nIn recent months, Microsoft Threat Intelligence has seen an increase in activity from threat actors leveraging social engineering and phishing techniques to target Windows OS users and utilizing the ms-appinstaller URI scheme.\\nTo address this increase in activity, we have updated the App Installer to disable the ms-appinstaller protocol by default and recommend other potential mitigations.\\n\"}, {\"lang\": \"es\", \"value\": \"Una vulnerabilidad de Suplantaci\\u00f3n de Identidad de Windows AppX Installer\"}]",
"id": "CVE-2021-43890",
"lastModified": "2024-11-21T06:29:59.457",
"metrics": "{\"cvssMetricV31\": [{\"source\": \"secure@microsoft.com\", \"type\": \"Secondary\", \"cvssData\": {\"version\": \"3.1\", \"vectorString\": \"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H\", \"baseScore\": 7.1, \"baseSeverity\": \"HIGH\", \"attackVector\": \"NETWORK\", \"attackComplexity\": \"HIGH\", \"privilegesRequired\": \"LOW\", \"userInteraction\": \"REQUIRED\", \"scope\": \"UNCHANGED\", \"confidentialityImpact\": \"HIGH\", \"integrityImpact\": \"HIGH\", \"availabilityImpact\": \"HIGH\"}, \"exploitabilityScore\": 1.2, \"impactScore\": 5.9}, {\"source\": \"nvd@nist.gov\", \"type\": \"Primary\", \"cvssData\": {\"version\": \"3.1\", \"vectorString\": \"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H\", \"baseScore\": 7.1, \"baseSeverity\": \"HIGH\", \"attackVector\": \"NETWORK\", \"attackComplexity\": \"HIGH\", \"privilegesRequired\": \"LOW\", \"userInteraction\": \"REQUIRED\", \"scope\": \"UNCHANGED\", \"confidentialityImpact\": \"HIGH\", \"integrityImpact\": \"HIGH\", \"availabilityImpact\": \"HIGH\"}, \"exploitabilityScore\": 1.2, \"impactScore\": 5.9}], \"cvssMetricV2\": [{\"source\": \"nvd@nist.gov\", \"type\": \"Primary\", \"cvssData\": {\"version\": \"2.0\", \"vectorString\": \"AV:N/AC:M/Au:S/C:P/I:P/A:P\", \"baseScore\": 6.0, \"accessVector\": \"NETWORK\", \"accessComplexity\": \"MEDIUM\", \"authentication\": \"SINGLE\", \"confidentialityImpact\": \"PARTIAL\", \"integrityImpact\": \"PARTIAL\", \"availabilityImpact\": \"PARTIAL\"}, \"baseSeverity\": \"MEDIUM\", \"exploitabilityScore\": 6.8, \"impactScore\": 6.4, \"acInsufInfo\": false, \"obtainAllPrivilege\": false, \"obtainUserPrivilege\": false, \"obtainOtherPrivilege\": false, \"userInteractionRequired\": true}]}",
"published": "2021-12-15T15:15:11.207",
"references": "[{\"url\": \"https://github.com/ChrisTitusTech/winutil/pull/26\", \"source\": \"secure@microsoft.com\", \"tags\": [\"Issue Tracking\"]}, {\"url\": \"https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43890\", \"source\": \"secure@microsoft.com\", \"tags\": [\"Patch\", \"Vendor Advisory\"]}, {\"url\": \"https://thehackernews.com/2023/12/microsoft-disables-msix-app-installer.html\", \"source\": \"secure@microsoft.com\", \"tags\": [\"Press/Media Coverage\", \"Third Party Advisory\"]}, {\"url\": \"https://www.bleepingcomputer.com/news/microsoft/microsoft-disables-msix-protocol-handler-abused-in-malware-attacks/\", \"source\": \"secure@microsoft.com\", \"tags\": [\"Press/Media Coverage\", \"Third Party Advisory\"]}, {\"url\": \"https://www.microsoft.com/en-us/security/blog/2023/12/28/financially-motivated-threat-actors-misusing-app-installer/\", \"source\": \"secure@microsoft.com\", \"tags\": [\"Exploit\", \"Vendor Advisory\"]}, {\"url\": \"https://github.com/ChrisTitusTech/winutil/pull/26\", \"source\": \"af854a3a-2127-422b-91ae-364da2661108\", \"tags\": [\"Issue Tracking\"]}, {\"url\": \"https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43890\", \"source\": \"af854a3a-2127-422b-91ae-364da2661108\", \"tags\": [\"Patch\", \"Vendor Advisory\"]}, {\"url\": \"https://thehackernews.com/2023/12/microsoft-disables-msix-app-installer.html\", \"source\": \"af854a3a-2127-422b-91ae-364da2661108\", \"tags\": [\"Press/Media Coverage\", \"Third Party Advisory\"]}, {\"url\": \"https://www.bleepingcomputer.com/news/microsoft/microsoft-disables-msix-protocol-handler-abused-in-malware-attacks/\", \"source\": \"af854a3a-2127-422b-91ae-364da2661108\", \"tags\": [\"Press/Media Coverage\", \"Third Party Advisory\"]}, {\"url\": \"https://www.microsoft.com/en-us/security/blog/2023/12/28/financially-motivated-threat-actors-misusing-app-installer/\", \"source\": \"af854a3a-2127-422b-91ae-364da2661108\", \"tags\": [\"Exploit\", \"Vendor Advisory\"]}]",
"sourceIdentifier": "secure@microsoft.com",
"vulnStatus": "Modified",
"weaknesses": "[{\"source\": \"nvd@nist.gov\", \"type\": \"Primary\", \"description\": [{\"lang\": \"en\", \"value\": \"NVD-CWE-noinfo\"}]}]"
},
"nvd": "{\"cve\":{\"id\":\"CVE-2021-43890\",\"sourceIdentifier\":\"secure@microsoft.com\",\"published\":\"2021-12-15T15:15:11.207\",\"lastModified\":\"2026-08-06T05:16:36.653\",\"vulnStatus\":\"Analyzed\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"We have investigated reports of a spoofing vulnerability in AppX installer that affects Microsoft Windows. Microsoft is aware of attacks that attempt to exploit this vulnerability by using specially crafted packages that include the malware family known as Emotet/Trickbot/Bazaloader.\\nAn attacker could craft a malicious attachment to be used in phishing campaigns. The attacker would then have to convince the user to open the specially crafted attachment. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.\\nPlease see the Security Updates table for the link to the updated app. Alternatively you can download and install the Installer using the links provided in the FAQ section.\\nPlease see the Mitigations and Workaround sections for important information about steps you can take to protect your system from this vulnerability.\\nDecember 27 2023 Update:\\nIn recent months, Microsoft Threat Intelligence has seen an increase in activity from threat actors leveraging social engineering and phishing techniques to target Windows OS users and utilizing the ms-appinstaller URI scheme.\\nTo address this increase in activity, we have updated the App Installer to disable the ms-appinstaller protocol by default and recommend other potential mitigations.\"},{\"lang\":\"es\",\"value\":\"Una vulnerabilidad de Suplantaci\u00f3n de Identidad de Windows AppX Installer\"}],\"affected\":[{\"source\":\"secure@microsoft.com\",\"affectedData\":[{\"vendor\":\"Microsoft\",\"product\":\"App Installer\",\"cpes\":[\"cpe:2.3:a:microsoft:app_installer:*:*:*:*:*:*:*:*\"],\"platforms\":[\"Unknown\"],\"versions\":[{\"version\":\"1.0.0.0\",\"lessThan\":\"publication\",\"versionType\":\"custom\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"secure@microsoft.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H\",\"baseScore\":7.1,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"HIGH\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"REQUIRED\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.2,\"impactScore\":5.9},{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H\",\"baseScore\":7.1,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"HIGH\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"REQUIRED\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.2,\"impactScore\":5.9}],\"cvssMetricV2\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"2.0\",\"vectorString\":\"AV:N/AC:M/Au:S/C:P/I:P/A:P\",\"baseScore\":6.0,\"accessVector\":\"NETWORK\",\"accessComplexity\":\"MEDIUM\",\"authentication\":\"SINGLE\",\"confidentialityImpact\":\"PARTIAL\",\"integrityImpact\":\"PARTIAL\",\"availabilityImpact\":\"PARTIAL\"},\"baseSeverity\":\"MEDIUM\",\"exploitabilityScore\":6.8,\"impactScore\":6.4,\"acInsufInfo\":false,\"obtainAllPrivilege\":false,\"obtainUserPrivilege\":false,\"obtainOtherPrivilege\":false,\"userInteractionRequired\":true}],\"ssvcV203\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"ssvcData\":{\"timestamp\":\"2021-12-14T00:00:00+00:00\",\"id\":\"CVE-2021-43890\",\"options\":[{\"exploitation\":\"active\"},{\"automatable\":\"no\"},{\"technicalImpact\":\"total\"}],\"role\":\"CISA Coordinator\",\"version\":\"2.0.3\"}}]},\"cisaExploitAdd\":\"2021-12-15\",\"cisaActionDue\":\"2021-12-29\",\"cisaRequiredAction\":\"Apply updates per vendor instructions.\",\"cisaVulnerabilityName\":\"Microsoft Windows AppX Installer Spoofing Vulnerability\",\"weaknesses\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"NVD-CWE-noinfo\"}]}],\"configurations\":[{\"operator\":\"AND\",\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:microsoft:app_installer:*:*:*:*:*:*:*:*\",\"versionEndExcluding\":\"1.16\",\"matchCriteriaId\":\"F5F1F637-0D18-4CBE-A56B-DEA530ACC1B0\"}]},{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":false,\"criteria\":\"cpe:2.3:o:microsoft:windows_10_1809:-:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"2E332666-2E03-468E-BC30-299816D6E8ED\"},{\"vulnerable\":false,\"criteria\":\"cpe:2.3:o:microsoft:windows_10_1903:-:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"A363CE8F-F399-4B6E-9E7D-349792F95DDB\"},{\"vulnerable\":false,\"criteria\":\"cpe:2.3:o:microsoft:windows_10_1909:-:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"A1B570A8-ED1A-46B6-B8AB-064445F8FC4C\"},{\"vulnerable\":false,\"criteria\":\"cpe:2.3:o:microsoft:windows_10_2004:-:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"D4DBE5B2-AE10-4251-BCDA-DC5EDEE6EE67\"},{\"vulnerable\":false,\"criteria\":\"cpe:2.3:o:microsoft:windows_10_20h2:-:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"6AFD13A6-A390-4400-9029-2F4058CA17E2\"},{\"vulnerable\":false,\"criteria\":\"cpe:2.3:o:microsoft:windows_10_21h1:-:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"B1FED4C9-B680-4F44-ADC0-AC43D6B5F184\"},{\"vulnerable\":false,\"criteria\":\"cpe:2.3:o:microsoft:windows_10_21h2:-:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"2F513002-D8C1-4D3A-9F79-4B52498F67E9\"},{\"vulnerable\":false,\"criteria\":\"cpe:2.3:o:microsoft:windows_11_21h2:-:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"BB4AE761-6FAC-4000-A63D-42CE3FAB8412\"}]}]},{\"operator\":\"AND\",\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:microsoft:app_installer:*:*:*:*:*:*:*:*\",\"versionEndExcluding\":\"1.11\",\"matchCriteriaId\":\"62B0A730-2442-4C85-8CFA-098D4DADFF8C\"}]},{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":false,\"criteria\":\"cpe:2.3:o:microsoft:windows_10_1507:-:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"542DAEEC-73CC-46C6-A630-BF474A3446AC\"},{\"vulnerable\":false,\"criteria\":\"cpe:2.3:o:microsoft:windows_10_1709:-:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"AC160B20-3EA0-49A0-A857-4E7A1C2D74E2\"},{\"vulnerable\":false,\"criteria\":\"cpe:2.3:o:microsoft:windows_10_1803:-:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"00345596-E9E0-4096-8DC6-0212F4747A13\"}]}]}],\"references\":[{\"url\":\"https://github.com/ChrisTitusTech/winutil/pull/26\",\"source\":\"secure@microsoft.com\",\"tags\":[\"Issue Tracking\"]},{\"url\":\"https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43890\",\"source\":\"secure@microsoft.com\",\"tags\":[\"Patch\",\"Vendor Advisory\"]},{\"url\":\"https://thehackernews.com/2023/12/microsoft-disables-msix-app-installer.html\",\"source\":\"secure@microsoft.com\",\"tags\":[\"Press/Media Coverage\",\"Third Party Advisory\"]},{\"url\":\"https://www.bleepingcomputer.com/news/microsoft/microsoft-disables-msix-protocol-handler-abused-in-malware-attacks/\",\"source\":\"secure@microsoft.com\",\"tags\":[\"Press/Media Coverage\",\"Third Party Advisory\"]},{\"url\":\"https://www.microsoft.com/en-us/security/blog/2023/12/28/financially-motivated-threat-actors-misusing-app-installer/\",\"source\":\"secure@microsoft.com\",\"tags\":[\"Exploit\",\"Vendor Advisory\"]},{\"url\":\"https://github.com/ChrisTitusTech/winutil/pull/26\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Issue Tracking\"]},{\"url\":\"https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43890\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\",\"Vendor Advisory\"]},{\"url\":\"https://thehackernews.com/2023/12/microsoft-disables-msix-app-installer.html\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Press/Media Coverage\",\"Third Party Advisory\"]},{\"url\":\"https://www.bleepingcomputer.com/news/microsoft/microsoft-disables-msix-protocol-handler-abused-in-malware-attacks/\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Press/Media Coverage\",\"Third Party Advisory\"]},{\"url\":\"https://www.microsoft.com/en-us/security/blog/2023/12/28/financially-motivated-threat-actors-misusing-app-installer/\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Exploit\",\"Vendor Advisory\"]},{\"url\":\"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-43890\",\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"tags\":[\"US Government Resource\"]}]}}",
"redhat_vex": {
"current_release_date": "2026-03-27T13:21:10+00:00",
"cve": "CVE-2021-43890",
"id": "CVE-2021-43890",
"initial_release_date": "2021-12-14T08:00:00+00:00",
"product_status:known_not_affected": "1",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "Windows AppX Installer Spoofing Vulnerability",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-43890.json",
"version": "3"
},
"vulnrichment": {
"containers": "{\"adp\": [{\"title\": \"CVE Program Container\", \"references\": [{\"url\": \"https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43890\", \"tags\": [\"x_refsource_MISC\", \"x_transferred\"]}, {\"url\": \"https://www.bleepingcomputer.com/news/microsoft/microsoft-disables-msix-protocol-handler-abused-in-malware-attacks/\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://thehackernews.com/2023/12/microsoft-disables-msix-app-installer.html\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://www.microsoft.com/en-us/security/blog/2023/12/28/financially-motivated-threat-actors-misusing-app-installer/\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://github.com/ChrisTitusTech/winutil/pull/26\", \"tags\": [\"x_transferred\"]}], \"providerMetadata\": {\"orgId\": \"af854a3a-2127-422b-91ae-364da2661108\", \"shortName\": \"CVE\", \"dateUpdated\": \"2024-08-04T04:10:17.079Z\"}}, {\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2021-43890\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"active\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"total\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-08-05T20:33:55.454012Z\"}}}, {\"other\": {\"type\": \"kev\", \"content\": {\"dateAdded\": \"2021-12-15\", \"reference\": \"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-43890\"}}}], \"references\": [{\"url\": \"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-43890\", \"tags\": [\"government-resource\"]}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"description\": \"CWE-noinfo Not enough information\"}]}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2025-02-04T16:04:44.546Z\"}}], \"cna\": {\"title\": \"Windows AppX Installer Spoofing Vulnerability\", \"metrics\": [{\"format\": \"CVSS\", \"cvssV3_1\": {\"version\": \"3.1\", \"baseScore\": 7.1, \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C\"}, \"scenarios\": [{\"lang\": \"en-US\", \"value\": \"GENERAL\"}]}], \"affected\": [{\"cpes\": [\"cpe:2.3:a:microsoft:app_installer:*:*:*:*:*:*:*:*\"], \"vendor\": \"Microsoft\", \"product\": \"App Installer\", \"versions\": [{\"status\": \"affected\", \"version\": \"1.0.0.0\", \"lessThan\": \"publication\", \"versionType\": \"custom\"}], \"platforms\": [\"Unknown\"]}], \"datePublic\": \"2021-12-14T08:00:00.000Z\", \"references\": [{\"url\": \"https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43890\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://www.bleepingcomputer.com/news/microsoft/microsoft-disables-msix-protocol-handler-abused-in-malware-attacks/\"}, {\"url\": \"https://thehackernews.com/2023/12/microsoft-disables-msix-app-installer.html\"}, {\"url\": \"https://www.microsoft.com/en-us/security/blog/2023/12/28/financially-motivated-threat-actors-misusing-app-installer/\"}, {\"url\": \"https://github.com/ChrisTitusTech/winutil/pull/26\"}], \"descriptions\": [{\"lang\": \"en-US\", \"value\": \"We have investigated reports of a spoofing vulnerability in AppX installer that affects Microsoft Windows. Microsoft is aware of attacks that attempt to exploit this vulnerability by using specially crafted packages that include the malware family known as Emotet/Trickbot/Bazaloader.\\nAn attacker could craft a malicious attachment to be used in phishing campaigns. The attacker would then have to convince the user to open the specially crafted attachment. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.\\nPlease see the Security Updates table for the link to the updated app. Alternatively you can download and install the Installer using the links provided in the FAQ section.\\nPlease see the Mitigations and Workaround sections for important information about steps you can take to protect your system from this vulnerability.\\nDecember 27 2023 Update:\\nIn recent months, Microsoft Threat Intelligence has seen an increase in activity from threat actors leveraging social engineering and phishing techniques to target Windows OS users and utilizing the ms-appinstaller URI scheme.\\nTo address this increase in activity, we have updated the App Installer to disable the ms-appinstaller protocol by default and recommend other potential mitigations.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en-US\", \"type\": \"Impact\", \"description\": \"Spoofing\"}]}], \"providerMetadata\": {\"orgId\": \"f38d906d-7342-40ea-92c1-6c4a2c6478c8\", \"shortName\": \"microsoft\", \"dateUpdated\": \"2024-05-29T14:44:37.753Z\"}}}",
"cveMetadata": "{\"cveId\": \"CVE-2021-43890\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-08-06T03:55:23.978Z\", \"dateReserved\": \"2021-11-16T00:00:00.000Z\", \"assignerOrgId\": \"f38d906d-7342-40ea-92c1-6c4a2c6478c8\", \"datePublished\": \"2021-12-15T14:15:35.000Z\", \"assignerShortName\": \"microsoft\"}",
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.