CVE-2024-49026Public exploit

Code execution via best-fit filename argument injection

Published Nov 12, 2024 · Updated Jul 8, 2025

Command injection in affected Microsoft Excel releases allows attackers to execute code after a user opens a crafted file name. Excel converts attacker-controlled fullwidth characters in the file name through Windows best-fit mapping, producing command-line separators that inject a UNC path into its launch arguments. Exploitation requires user interaction and a Windows environment where relayed NTLM authentication can be converted into code execution.

CVSS severity7.8
High
EPSS probability0.96%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Command injection in affected Microsoft Excel releases allows attackers to execute code after a user opens a crafted file name. Excel converts attacker-controlled fullwidth characters in the file name through Windows best-fit mapping, producing command-line separators that inject a UNC path into its launch arguments. Exploitation requires user interaction and a Windows environment where relayed NTLM authentication can be converted into code execution.

The record

CVE
CVE-2024-49026
Published
Nov 12, 2024
Updated
Jul 8, 2025
Vendor
Microsoft
Product
Microsoft Office 2019
Classifications
CWE-77, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 12, 2024CVE publishedPublication date reported by the CVE source.
  2. Jul 8, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

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 Excel 2016version=16.0.0 <16.0.5474.1001
Microsoft · Microsoft Office LTSC 2021version=16.0.1 <https://aka.ms/OfficeSecurityReleases
Microsoft · Microsoft Office LTSC 2024version=1.0.0 <https://aka.ms/OfficeSecurityReleases
Microsoft · Office Online Serverversion=16.0.1 <16.0.10416.20007
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 exploitPublished

Weakness, pattern, technique

CWE-77Improper Neutralization of Special Elements used in a Command ('Command Injection')
T1204.002Malicious File

Public exploit references

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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