CVE-2021-34468

Service-account code execution via CAB path traversal

Published Jul 14, 2021 · Updated Aug 10, 2026

Path traversal in Microsoft SharePoint Server allows attackers to execute service-account code via a crafted CAB file. CabUtility's ExtractCab routine fails to validate user-supplied filenames before using their paths in file operations, permitting extraction outside the intended directory. Exploitation requires user interaction, adjacent-network access, and another vulnerability in a chain; successful execution runs in the SharePoint service-account context.

CVSS severity7.1
High
EPSS probability2.13%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in Microsoft SharePoint Server allows attackers to execute service-account code via a crafted CAB file. CabUtility's ExtractCab routine fails to validate user-supplied filenames before using their paths in file operations, permitting extraction outside the intended directory. Exploitation requires user interaction, adjacent-network access, and another vulnerability in a chain; successful execution runs in the SharePoint service-account context.

The record

CVE
CVE-2021-34468
Published
Jul 14, 2021
Updated
Aug 10, 2026
Vendor
Microsoft
Product
Microsoft SharePoint Foundation 2013
Classifications
T1204.002
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 14, 2021CVE 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=15.0.0 <15.0.5363.1000

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Microsoft · Microsoft SharePoint Foundation 2013version=15.0.0 <15.0.5363.1000
Microsoft · Microsoft SharePoint Enterprise Server 2016version=16.0.0 <16.0.5188.1000
Microsoft · Microsoft SharePoint Server 2019version=16.0.0 <16.0.10376.20001

Published CVSS scores

8.0NIST NVDCVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
5.4NIST NVDAV:A/AC:M/Au:N/C:P/I:P/A:P
7.1Microsoft CorporationCVSS:3.1/AV:A/AC:H/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 11, 2026Sep 17, 2026
Latest reporting daySep 17, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1204.002Malicious 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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