CVE-2026-41091 (GCVE-0-2026-41091)

Vulnerability from cvelistv5 – Published: 2026-05-20 13:09 – Updated: 2026-05-22 22:03
VLAI? CISA KEV
Title
Microsoft Defender Elevation of Privilege Vulnerability
Summary
Improper link resolution before file access ('link following') in Microsoft Defender allows an authorized attacker to elevate privileges locally.
Severity ?
7.8 (High)
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
CWE
  • CWE-59 - Improper Link Resolution Before File Access ('Link Following')
Assigner
References
Impacted products
Date Public ?
2026-05-19 14:00
CISA KEV
Known Exploited Vulnerability - GCVE BCP-07 Compliant
KEV entry ID: 585a485a-b1a5-49e8-8e94-9e2a71a3efb4

Vulnerability ID: CVE-2026-41091

Status: Confirmed

Status Updated: 2026-05-20 00:00 UTC

Exploited: Yes

Timestamps
First Seen: 2026-05-20
Asserted: 2026-05-20
Scope
Notes: KEV entry: Microsoft Defender Link Following Vulnerability | Affected: Microsoft / Defender | Description: Microsoft Defender contains a link following vulnerability that allows an authorized attacker to elevate privileges locally. | 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. | Due date: 2026-06-03 | Known ransomware campaign use (KEV): Unknown | Notes (KEV): https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-41091 ; https://nvd.nist.gov/vuln/detail/CVE-2026-41091
Evidence

Type: Vendor Report

Signal: Successful Exploitation

Confidence: 80%

Source: cisa-kev

Details
Cwes CWE-59
Feed CISA Known Exploited Vulnerabilities Catalog
Product Defender
Due Date 2026-06-03
Date Added 2026-05-20
Vendorproject Microsoft
Vulnerabilityname Microsoft Defender Link Following Vulnerability
Knownransomwarecampaignuse Unknown
References
Created: 2026-05-20 18:00 UTC | Updated: 2026-05-20 18:00 UTC
Show details on NVD website
To clipboard 

{
  "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": [
            {
              "status": "affected",
              "version": "-"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:microsoft:malware_protection_engine:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "-",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "datePublic": "2026-05-19T14:00:00.000Z",
      "descriptions": [
        {
          "lang": "en-US",
          "value": "Improper link resolution before file access (\u0027link following\u0027) 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 (\u0027Link Following\u0027)",
              "lang": "en-US",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-22T22:03:59.591Z",
        "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": "2026-05-22T22:03:59.591Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "cisa_known_exploited": {
      "cveID": "CVE-2026-41091",
      "cwes": "[\"CWE-59\"]",
      "dateAdded": "2026-05-20",
      "dueDate": "2026-06-03",
      "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"
    },
    "epss": {
      "cve": "CVE-2026-41091",
      "date": "2026-05-23",
      "epss": "0.05225",
      "percentile": "0.90054"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-41091\",\"sourceIdentifier\":\"secure@microsoft.com\",\"published\":\"2026-05-20T13:16:29.173\",\"lastModified\":\"2026-05-20T19:06:36.850\",\"vulnStatus\":\"Analyzed\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"Improper link resolution before file access (\u0027link following\u0027) in Microsoft Defender allows an authorized attacker to elevate privileges locally.\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"secure@microsoft.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":7.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9}]},\"cisaExploitAdd\":\"2026-05-20\",\"cisaActionDue\":\"2026-06-03\",\"cisaRequiredAction\":\"Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.\",\"cisaVulnerabilityName\":\"Microsoft Defender Link Following Vulnerability\",\"weaknesses\":[{\"source\":\"secure@microsoft.com\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-59\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:microsoft:malware_protection_engine:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"1.1.26030.3008\",\"versionEndExcluding\":\"1.1.26040.8\",\"matchCriteriaId\":\"AD1882FA-1447-46F7-A592-142F55820A60\"}]}]}],\"references\":[{\"url\":\"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-41091\",\"source\":\"secure@microsoft.com\",\"tags\":[\"Vendor Advisory\"]},{\"url\":\"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-41091\",\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"tags\":[\"US Government Resource\",\"Third Party Advisory\"]}]}}",
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-41091\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"active\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"total\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-05-20T17:12:43.312897Z\"}}}, {\"other\": {\"type\": \"kev\", \"content\": {\"dateAdded\": \"2026-05-20\", \"reference\": \"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-41091\"}}}], \"references\": [{\"url\": \"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-41091\", \"tags\": [\"government-resource\"]}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-05-20T17:13:03.067Z\"}, \"timeline\": [{\"lang\": \"en\", \"time\": \"2026-05-20T00:00:00.000Z\", \"value\": \"CVE-2026-41091 added to CISA KEV\"}]}], \"cna\": {\"title\": \"Microsoft Defender Elevation of Privilege Vulnerability\", \"metrics\": [{\"format\": \"CVSS\", \"cvssV3_1\": {\"version\": \"3.1\", \"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\"}, \"scenarios\": [{\"lang\": \"en-US\", \"value\": \"GENERAL\"}]}], \"affected\": [{\"vendor\": \"Microsoft\", \"product\": \"Microsoft Malware Protection Engine\", \"versions\": [{\"status\": \"affected\", \"version\": \"-\"}]}], \"datePublic\": \"2026-05-19T14:00:00.000Z\", \"references\": [{\"url\": \"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-41091\", \"name\": \"Microsoft Defender Elevation of Privilege Vulnerability\", \"tags\": [\"vendor-advisory\", \"patch\"]}], \"descriptions\": [{\"lang\": \"en-US\", \"value\": \"Improper link resolution before file access (\u0027link following\u0027) in Microsoft Defender allows an authorized attacker to elevate privileges locally.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en-US\", \"type\": \"CWE\", \"cweId\": \"CWE-59\", \"description\": \"CWE-59: Improper Link Resolution Before File Access (\u0027Link Following\u0027)\"}]}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:a:microsoft:malware_protection_engine:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionStartIncluding\": \"-\"}], \"operator\": \"OR\"}]}], \"providerMetadata\": {\"orgId\": \"f38d906d-7342-40ea-92c1-6c4a2c6478c8\", \"shortName\": \"microsoft\", \"dateUpdated\": \"2026-05-22T22:03:59.591Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-41091\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-05-22T22:03:59.591Z\", \"dateReserved\": \"2026-04-16T19:12:36.195Z\", \"assignerOrgId\": \"f38d906d-7342-40ea-92c1-6c4a2c6478c8\", \"datePublished\": \"2026-05-20T13:09:13.634Z\", \"assignerShortName\": \"microsoft\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.



Detection rules are retrieved from Rulezet.