CVE-2026-55121 (GCVE-0-2026-55121)

Vulnerability from cvelistv5 – Published: 2026-07-14 17:10 – Updated: 2026-08-10 17:21
VLAI
Title
Microsoft Office Information Disclosure Vulnerability
Summary
Out-of-bounds read in Microsoft Office allows an unauthorized attacker to disclose information locally.
Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-07-14 17:46 UTC
CWE
Assigner
References
Impacted products
Vendor Product Version
Microsoft Microsoft 365 Apps for Enterprise Affected: 16.0.1 , < https://aka.ms/OfficeSecurityReleases (custom)
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Microsoft Microsoft Office 2016 Affected: 16.0.0 , < 16.0.5561.1000 (custom)
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Microsoft Microsoft Office 2019 Affected: 19.0.0 , < https://aka.ms/OfficeSecurityReleases (custom)
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Microsoft Microsoft Office 365 for Mac Affected: 1.0.0 , < 16.111.26071215 (custom)
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Microsoft Microsoft Office LTSC 2021 Affected: 16.0.1 , < https://aka.ms/OfficeSecurityReleases (custom)
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Microsoft Microsoft Office LTSC 2024 Affected: 16.0.0 , < https://aka.ms/OfficeSecurityReleases (custom)
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Microsoft Microsoft Office LTSC for Mac 2021 Affected: 16.0.1 , < 16.111.26071215 (custom)
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Microsoft Microsoft Office LTSC for Mac 2024 Affected: 16.0.0 , < 16.111.26071215 (custom)
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Microsoft Microsoft SharePoint Enterprise Server 2016 Affected: 16.0.0 , < 16.0.5561.1001 (custom)
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Microsoft Microsoft SharePoint Server 2019 Affected: 16.0.0 , < 16.0.10417.20175 (custom)
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Microsoft Microsoft SharePoint Server Subscription Edition Affected: 16.0.0 , < 16.0.19725.20434 (custom)
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Date Public
2026-07-14 14:00
Show details on NVD website
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[\"vendor-advisory\", \"patch\"]}], \"descriptions\": [{\"lang\": \"en-US\", \"value\": \"Out-of-bounds read in Microsoft Office allows an unauthorized attacker to disclose information locally.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en-US\", \"type\": \"CWE\", \"cweId\": \"CWE-125\", \"description\": \"CWE-125: Out-of-bounds Read\"}]}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:a:microsoft:office_365:*:*:*:*:*:macos:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"16.111.26071215\", \"versionStartIncluding\": \"1.0.0\"}, {\"criteria\": \"cpe:2.3:a:microsoft:sharepoint_server_2016:*:*:*:*:enterprise:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"16.0.5561.1001\", \"versionStartIncluding\": \"16.0.0\"}, {\"criteria\": \"cpe:2.3:a:microsoft:sharepoint_server_2019:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"16.0.10417.20175\", \"versionStartIncluding\": \"16.0.0\"}, {\"criteria\": \"cpe:2.3:a:microsoft:office_2019:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"https://aka.ms/OfficeSecurityReleases\", \"versionStartIncluding\": \"19.0.0\"}, {\"criteria\": \"cpe:2.3:a:microsoft:365_apps:*:*:*:*:enterprise:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"https://aka.ms/OfficeSecurityReleases\", \"versionStartIncluding\": \"16.0.1\"}, {\"criteria\": \"cpe:2.3:a:microsoft:office_macos_2021:*:*:*:*:*:long_term_servicing_channel:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"16.111.26071215\", \"versionStartIncluding\": \"16.0.1\"}, {\"criteria\": \"cpe:2.3:a:microsoft:office_2021:*:*:*:*:long_term_servicing_channel:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"https://aka.ms/OfficeSecurityReleases\", \"versionStartIncluding\": \"16.0.1\"}, {\"criteria\": \"cpe:2.3:a:microsoft:sharepoint_server:*:*:*:*:subscription:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"16.0.19725.20434\", \"versionStartIncluding\": \"16.0.0\"}, {\"criteria\": \"cpe:2.3:a:microsoft:office_2024:*:*:*:*:long_term_servicing_channel:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"https://aka.ms/OfficeSecurityReleases\", \"versionStartIncluding\": \"16.0.0\"}, {\"criteria\": \"cpe:2.3:a:microsoft:office_macos_2024:*:*:*:*:*:long_term_servicing_channel:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"16.111.26071215\", \"versionStartIncluding\": \"16.0.0\"}, {\"criteria\": \"cpe:2.3:a:microsoft:office_2016:*:*:*:*:*:*:x86:*\", \"vulnerable\": true, \"versionEndExcluding\": \"16.0.5561.1000\", \"versionStartIncluding\": \"16.0.0\"}], \"operator\": \"OR\"}]}], \"providerMetadata\": {\"orgId\": \"f38d906d-7342-40ea-92c1-6c4a2c6478c8\", \"shortName\": \"microsoft\", \"dateUpdated\": \"2026-08-03T22:59:05.341Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-55121\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-08-03T22:59:05.341Z\", \"dateReserved\": \"2026-06-16T15:03:49.680Z\", \"assignerOrgId\": \"f38d906d-7342-40ea-92c1-6c4a2c6478c8\", \"datePublished\": \"2026-07-14T17:10:17.586Z\", \"assignerShortName\": \"microsoft\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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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.