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Vulnerabilities/CVE-2026-54988Public Intelligence Dossier
Source: microsoft · Limited verification•Last verified: •Collection Running
CVE-2026-54988Unknown / EvaluatingMEDIUM (raw)CVSS 6.1CWE-125

Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information locally.

Published: 14 Jul 2026•Last updated: 15 Oct 2026, 03:40 AM IST•Source identifier: secure@microsoft.com
Dossier completeness: source-provided sections 2 / 3 · rule guidance not available. Missing source facts count as incomplete.
Official source
CISA KEV catalog
Unknown
KEV status was not determined.
CVSS score
6.1MEDIUM (raw)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H
Metric sourcesecure@microsoft.com
EPSS probability
0.5%0.005
Percentile39th
Weakness type
CWE-125
No further CWE recorded
Remediation
Patch status unknown
No fixed version or KB recorded

Why It Matters

Analysis dossier

Why It Matters

Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information locally.

SOC priority

Medium

Actively exploited

Unknown

Publicly disclosed

Unknown

Risk basis: Microsoft or Microsoft-managed product relevance; No confirmed exploitation signal in current enrichment

Affected Products & Remediation

7 source-backed products
Affected products and versions (source)
  • microsoft 365 apps · version range not provided by source · NVD CPE · Source
  • microsoft excel · 2016 · NVD CPE · Source
  • microsoft microsoft 365 · version range not provided by source · NVD CPE · Source
  • microsoft office 2019 · version range not provided by source · NVD CPE · Source
  • microsoft office 2021 · version range not provided by source · NVD CPE · Source
  • microsoft office 2024 · version range not provided by source · NVD CPE · Source
  • microsoft office online server · < 16.0.10417.20175 · NVD CPE · Source
Recorded patch / KBNot provided by source

Vendor or catalog guidance (source)

Not provided by source

Known exploitation (source facts)

Only what a source states. Unknown means no source has said either way; it is not "not exploited".

CISA KEV
Unknown
Exploited (source statement)
Unknown
Publicly disclosed (source)
Unknown

Suggested hunting (rule-based inference)

SecOps Signal recommendation (rule-based inference). These steps are hunting hypotheses from the vulnerability class; they do not state or imply that exploitation occurred here or anywhere.

No rule-based guidance for this vulnerability class

CISA KEV Record

CISA KEV status was not determined for this record.

Change History & Source Data

— No recorded material change

CNA / source
secure@microsoft.com
Record status · verification
UPDATED · Microsoft primary source linked
CPE
cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:x64:*, cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:x86:*, cpe:2.3:a:microsoft:excel:2016:*:*:*:*:*:x64:*, cpe:2.3:a:microsoft:excel:2016:*:*:*:*:*:x86:*, cpe:2.3:a:microsoft:microsoft_365:-:*:*:*:*:macos:*:*, cpe:2.3:a:microsoft:office_2019:-:*:*:*:*:*:x64:*, cpe:2.3:a:microsoft:office_2019:-:*:*:*:*:*:x86:*, cpe:2.3:a:microsoft:office_2021:-:*:*:*:ltsc:-:x64:*, cpe:2.3:a:microsoft:office_2021:-:*:*:*:ltsc:-:x86:*, cpe:2.3:a:microsoft:office_2021:-:*:*:*:ltsc:macos:-:*

Evidence & Provenance

2 public sources
msrc.microsoft.comSource recordnvd.nist.govSource record

Linked by the query's stored exact CVE association. Review required tables and validation status before use.

Detection Hunting Query
Target: DeviceTvmSoftwareVulnerabilities•Defender XDR
Detect endpoints exposed to CVE-2026-54988
Purpose: Exposure assessment (Category: Exposure Check)Why linked: Query metadata names CVE-2026-54988
DeviceTvmSoftwareVulnerabilities| where CveId == "CVE-2026-54988"| project DeviceId, DeviceName, OSPlatform, OSVersion, SoftwareVendor, SoftwareName, SoftwareVersion, CveId, VulnerabilitySeverityLevel, RecommendedSecurityUpdate, RecommendedSecurityUpdateId| sort by VulnerabilitySeverityLevel desc
Schema Checked · Not runtime validatedSource: SecOps Signal deterministic template · Limited verificationStatic screening: Passed structure and schema checks; tenant execution is not verified.
Open KQL Library

Correlated briefings

— No published briefing references this CVE

SecOps Signal surfaces public advisory facts only. A missing value means the source has not published it, not that your environment is unaffected. No tenant inventory is connected.