November 13, 2026 Follow Egret
CVE-2023-35311 · CVE record: PUBLISHED

Microsoft Outlook Security Feature Bypass Vulnerability

Microsoft Microsoft 365 Apps for Enterprise, Microsoft Microsoft Office LTSC 2021, Microsoft Microsoft Office 2019, Microsoft Microsoft Outlook 2016, Microsoft Microsoft Outlook 2013, Microsoft Microsoft Outlook 2013 Service Pack 1

Microsoft Outlook Security Feature Bypass Vulnerability

Exploitation evidence

Known exploited · CISA KEV listed

Added 2023-07-11. Ransomware campaign use: Unknown.

CISA required action: Apply updates per vendor instructions or discontinue use of the product if updates are unavailable.

CISA due date: 2023-08-01. 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 365 Apps for Enterprise

Default status: Not specified

  • affected: 16.0.1 to < https://aka.ms/OfficeSecurityReleases (custom)

Microsoft / Microsoft Office LTSC 2021

Default status: Not specified

  • affected: 16.0.1 to < https://aka.ms/OfficeSecurityReleases (custom)

Microsoft / Microsoft Office 2019

Default status: Not specified

  • affected: 19.0.0 to < https://aka.ms/OfficeSecurityReleases (custom)

Microsoft / Microsoft Outlook 2016

Default status: Not specified

  • affected: 16.0.0.0 to < 16.0.5404.1000 (custom)

Microsoft / Microsoft Outlook 2013

Default status: Not specified

  • affected: 14.0.0 to < 15.0.5571.1000 (custom)

Microsoft / Microsoft Outlook 2013 Service Pack 1

Default status: Not specified

  • affected: 15.0.0.0 to < 15.0.5571.1000 (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

CVE Program record ↗ · Download tracked evidence as JSON

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": 0.15522,
  "percentile": 0.96858
}
10 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-10",
  "epss": 0.15522,
  "percentile": 0.96838
}
09 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-09",
  "epss": 0.15522,
  "percentile": 0.96835
}
08 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-08",
  "epss": 0.15522,
  "percentile": 0.96833
}
07 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-07",
  "epss": 0.15522,
  "percentile": 0.96831
}
06 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-06",
  "epss": 0.15522,
  "percentile": 0.96827
}
06 Nov 2026, 06:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-05",
  "epss": 0.15522,
  "percentile": 0.96826
}
04 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-04",
  "epss": 0.15522,
  "percentile": 0.96823
}
04 Nov 2026, 18:20 Jerusalem · CVE Program record changed

Stored CNA snapshot at this observation.

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-02T16:23:59.684Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "name": "Microsoft Outlook Security Feature Bypass Vulnerability",
            "tags": [
              "vendor-advisory",
              "x_transferred"
            ],
            "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-35311"
          }
        ],
        "title": "CVE Program Container"
      },
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2023-35311",
                "options": [
                  {
                    "Exploitation": "active"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-02-04T17:53:50.345525Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          },
          {
            "other": {
              "content": {
                "dateAdded": "2023-07-11",
                "reference": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-35311"
              },
              "type": "kev"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-10-07T17:43:22.867Z",
          "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-2023-35311"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "platforms": [
            "32-bit Systems",
            "x64-based Systems"
          ],
          "product": "Microsoft 365 Apps for Enterprise",
          "vendor": "Microsoft",
          "versions": [
            {
              "lessThan": "https://aka.ms/OfficeSecurityReleases",
              "status": "affected",
              "version": "16.0.1",
              "versionType": "custom"
            }
          ]
        },
        {
          "platforms": [
            "32-bit Systems",
            "x64-based Systems"
          ],
          "product": "Microsoft Office LTSC 2021",
          "vendor": "Microsoft",
          "versions": [
            {
              "lessThan": "https://aka.ms/OfficeSecurityReleases",
              "status": "affected",
              "version": "16.0.1",
              "versionType": "custom"
            }
          ]
        },
        {
          "platforms": [
            "32-bit Systems",
            "x64-based Systems"
          ],
          "product": "Microsoft Office 2019",
          "vendor": "Microsoft",
          "versions": [
            {
              "lessThan": "https://aka.ms/OfficeSecurityReleases",
              "status": "affected",
              "version": "19.0.0",
              "versionType": "custom"
            }
          ]
        },
        {
          "platforms": [
            "32-bit Systems",
            "x64-based Systems"
          ],
          "product": "Microsoft Outlook 2016",
          "vendor": "Microsoft",
          "versions": [
            {
              "lessThan": "16.0.5404.1000",
              "status": "affected",
              "version": "16.0.0.0",
              "versionType": "custom"
            }
          ]
        },
        {
          "platforms": [
            "32-bit Systems",
            "x64-based Systems"
          ],
          "product": "Microsoft Outlook 2013",
          "vendor": "Microsoft",
          "versions": [
            {
              "lessThan": "15.0.5571.1000",
              "status": "affected",
              "version": "14.0.0",
              "versionType": "custom"
            }
          ]
        },
        {
          "platforms": [
            "ARM64-based Systems"
          ],
          "product": "Microsoft Outlook 2013 Service Pack 1",
          "vendor": "Microsoft",
          "versions": [
            {
              "lessThan": "15.0.5571.1000",
              "status": "affected",
              "version": "15.0.0.0",
              "versionType": "custom"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:microsoft:365_apps:*:*:*:*:enterprise:*:*:*",
                  "versionEndExcluding": "https://aka.ms/OfficeSecurityReleases",
                  "versionStartIncluding": "16.0.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:a:microsoft:office_long_term_servicing_channel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "https://aka.ms/OfficeSecurityReleases",
                  "versionStartIncluding": "16.0.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:a:microsoft:office:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "https://aka.ms/OfficeSecurityReleases",
                  "versionStartIncluding": "19.0.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:a:microsoft:outlook:*:*:*:*:*:x86:*:*",
                  "versionEndExcluding": "16.0.5404.1000",
                  "versionStartIncluding": "16.0.0.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:a:microsoft:outlook:*:-:-:*:-:-:x86:*",
                  "versionEndExcluding": "15.0.5571.1000",
                  "versionStartIncluding": "14.0.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:a:microsoft:outlook:*:*:*:*:rt:*:*:*",
                  "versionEndExcluding": "15.0.5571.1000",
                  "versionStartIncluding": "15.0.0.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "datePublic": "2023-07-11T07:00:00.000Z",
      "descriptions": [
        {
          "lang": "en-US",
          "value": "Microsoft Outlook Security Feature Bypass Vulnerability"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en-US",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-367",
              "description": "CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition",
              "lang": "en-US",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-01-01T01:53:02.982Z",
        "orgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8",
        "shortName": "microsoft"
      },
      "references": [
        {
          "name": "Microsoft Outlook Security Feature Bypass Vulnerability",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-35311"
        }
      ],
      "title": "Microsoft Outlook Security Feature Bypass Vulnerability"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8",
    "assignerShortName": "microsoft",
    "cveId": "CVE-2023-35311",
    "datePublished": "2023-07-11T17:03:27.227Z",
    "dateReserved": "2023-06-14T23:09:47.613Z",
    "dateUpdated": "2026-10-07T17:43:22.867Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}
03 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-03",
  "epss": 0.15522,
  "percentile": 0.96817
}
03 Nov 2026, 02:22 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-02",
  "epss": 0.15522,
  "percentile": 0.96813
}
03 Nov 2026, 02:22 Jerusalem · CISA KEV status changed

Stored KEV snapshot at this observation.

{
  "cveID": "CVE-2023-35311",
  "cwes": [
    "CWE-367"
  ],
  "dateAdded": "2023-07-11",
  "dueDate": "2023-08-01",
  "forensicTriage": "No",
  "knownRansomwareCampaignUse": "Unknown",
  "notes": "https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2023-35311;  https://nvd.nist.gov/vuln/detail/CVE-2023-35311",
  "product": "Outlook",
  "requiredAction": "Apply updates per vendor instructions or discontinue use of the product if updates are unavailable.",
  "shortDescription": "Microsoft Outlook contains a security feature bypass vulnerability that allows an attacker to bypass the Microsoft Outlook Security Notice prompt.",
  "vendorProject": "Microsoft",
  "vulnerabilityName": "Microsoft Outlook Security Feature Bypass Vulnerability"
}
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