CVE-2025-21186

Code execution via crafted Access document

Published Jan 14, 2025 · Updated Jun 9, 2026

Heap-based buffer overflow in Microsoft Access allows attackers to execute code after a user opens a crafted Access document. Microsoft identifies CWE-122 but has not disclosed the affected parser, object, or exact memory operation that mishandles document data. Exploitation requires local processing and user interaction; successful exploitation runs attacker-controlled code in the user's security context.

CVSS severity7.8
High
EPSS probability1.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in Microsoft Access allows attackers to execute code after a user opens a crafted Access document. Microsoft identifies CWE-122 but has not disclosed the affected parser, object, or exact memory operation that mishandles document data. Exploitation requires local processing and user interaction; successful exploitation runs attacker-controlled code in the user's security context.

The record

CVE
CVE-2025-21186
Published
Jan 14, 2025
Updated
Jun 9, 2026
Vendor
Microsoft
Product
Microsoft Office 2019
Classifications
CWE-122, CAPEC-92, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 14, 2025CVE publishedPublication date reported by the CVE source.
  2. Jun 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=19.0.0 <https://aka.ms/OfficeSecurityReleases

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Microsoft · Microsoft Office 2019version=19.0.0 <https://aka.ms/OfficeSecurityReleases
Microsoft · Microsoft Access 2016 (32-bit edition)version=16.0.0 <16.0.5483.1001
Microsoft · Microsoft Office LTSC 2021version=16.0.1 <https://aka.ms/OfficeSecurityReleases
Microsoft · Microsoft Access 2016version=16.0.0 <16.0.5483.1001
Microsoft · Microsoft Office LTSC 2024version=16.0.0 <https://aka.ms/OfficeSecurityReleases
Microsoft · Microsoft 365 Apps for enterpriseversion=16.0.1 <https://aka.ms/OfficeSecurityReleases

Published CVSS scores

7.8Microsoft CorporationCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-122Heap-based Buffer Overflow
CAPEC-92Forced Integer Overflow
T1204.002User Execution: Malicious File

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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