FKIE_CVE-2026-42831

Vulnerability from fkie_nvd - Published: 2026-05-12 18:17 - Updated: 2026-05-22 14:49
Severity
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Summary
Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.
References
secure@microsoft.comhttps://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-42831Vendor Advisory
Impacted products
Vendor Product Version
microsoft 365_copilot *
microsoft office 2024
microsoft office_long_term_servicing_channel 2021
To clipboard 

{
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:microsoft:365_copilot:*:*:*:*:*:android:*:*",
              "matchCriteriaId": "71B289C6-6C8F-4217-AA2A-06931EE86372",
              "versionEndExcluding": "16.0.19822.20190",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:microsoft:office:2024:*:*:*:ltsc:macos:*:*",
              "matchCriteriaId": "873BD998-9D5A-4C09-A3B3-4DB12ABB6F72",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:microsoft:office_long_term_servicing_channel:2021:*:*:*:*:macos:*:*",
              "matchCriteriaId": "BF0E8112-5B6F-4E55-8E40-38ADCF6FC654",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally."
    }
  ],
  "id": "CVE-2026-42831",
  "lastModified": "2026-05-22T14:49:53.277",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "secure@microsoft.com",
        "type": "Primary"
      }
    ]
  },
  "published": "2026-05-12T18:17:25.673",
  "references": [
    {
      "source": "secure@microsoft.com",
      "tags": [
        "Vendor Advisory"
      ],
      "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-42831"
    }
  ],
  "sourceIdentifier": "secure@microsoft.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-122"
        }
      ],
      "source": "secure@microsoft.com",
      "type": "Primary"
    }
  ]
}


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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.