CVE-2023-35371

Code execution via Excel double free

Published Aug 8, 2023 · Updated Aug 10, 2026

Double-free in Microsoft Excel in affected Microsoft Office editions allows remote attackers to execute code via a crafted file. Microsoft identifies Excel and CWE-415 but has not disclosed the freed object, parser routine, or precise malformed-file operation. Exploitation requires a user to open the file, after which code runs in that user's application context.

CVSS severity7.8
High
EPSS probability0.98%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Double-free in Microsoft Excel in affected Microsoft Office editions allows remote attackers to execute code via a crafted file. Microsoft identifies Excel and CWE-415 but has not disclosed the freed object, parser routine, or precise malformed-file operation. Exploitation requires a user to open the file, after which code runs in that user's application context.

The record

CVE
CVE-2023-35371
Published
Aug 8, 2023
Updated
Aug 10, 2026
Vendor
Microsoft
Product
Microsoft Office 2019
Classifications
CWE-415, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 8, 2023CVE publishedPublication date reported by the CVE source.
  2. Aug 10, 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 Office LTSC for Mac 2021version=16.0.1 <16.76.23081101
Microsoft · Microsoft Office 2019 for Macversion=16.0.0 <16.76.23081101
Microsoft · Microsoft Office LTSC 2021version=16.0.1 <https://aka.ms/OfficeSecurityReleases
Microsoft · Microsoft Office Online Serverversion=16.0.1 <16.0.10401.20022
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-415Double Free
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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