CVE-2021-37617

Local privilege escalation via planted uninstaller

Published Aug 18, 2021 · Updated Aug 4, 2024

Untrusted search path handling in Nextcloud Desktop Client 3.0.3 through 3.2.4 allows local users to gain administrative execution. During installation, the client resolves a legacy Uninstall.exe from the user-writable C:\ root instead of reading the NSIS UninstallString registry value. A local user must plant the executable before an administrator runs the installer; the planted program then runs with administrative privileges.

CVSS severity7.3
High
EPSS probability0.46%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Untrusted search path handling in Nextcloud Desktop Client 3.0.3 through 3.2.4 allows local users to gain administrative execution. During installation, the client resolves a legacy Uninstall.exe from the user-writable C:\ root instead of reading the NSIS UninstallString registry value. A local user must plant the executable before an administrator runs the installer; the planted program then runs with administrative privileges.

The record

CVE
CVE-2021-37617
Published
Aug 18, 2021
Updated
Aug 4, 2024
Vendor
Nextcloud GmbH
Product
Nextcloud Security Advisories
Classifications
CWE-426, CWE-427, T1574.008
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 18, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record 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=>= 3.0.3 , <= 3.2.4

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Nextcloud GmbH · Nextcloud Security Advisoriesversion=>= 3.0.3 , <= 3.2.4

Published CVSS scores

4.4NIST NVDAV:L/AC:M/Au:N/C:P/I:P/A:P
7.3GitHub, Inc.CVSS:3.1/AV:L/AC:L/PR:L/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-426Untrusted Search Path
CWE-427Uncontrolled Search Path Element
T1574.008Path Interception by Search Order Hijacking

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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