CVE-2023-54331Public exploit

Local privilege escalation via unquoted service path

Published Jan 13, 2026 · Updated Jan 13, 2026

Unquoted service path in Outline Client 1.6.0 allows local users to execute code with LocalSystem privileges on Windows. The OutlineService registration supplies C:\Program Files (x86)\Outline\OutlineService.exe as an unquoted auto-start binary path while the service runs as LocalSystem. Local access and permission to place an executable in an earlier searched path segment are required for elevated code execution.

CVSS severity8.5
High
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Unquoted service path in Outline Client 1.6.0 allows local users to execute code with LocalSystem privileges on Windows. The OutlineService registration supplies C:\Program Files (x86)\Outline\OutlineService.exe as an unquoted auto-start binary path while the service runs as LocalSystem. Local access and permission to place an executable in an earlier searched path segment are required for elevated code execution.

The record

CVE
CVE-2023-54331
Published
Jan 13, 2026
Updated
Jan 13, 2026
Vendor
Outline Foundation
Product
Outline Client
Classifications
CWE-428, T1574.009
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 13, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 13, 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=1.6.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Outline Foundation · Outline Clientversion=1.6.0

Published CVSS scores

8.5VulnCheckCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
7.8VulnCheckCVSS:3.1/AV:L/AC:L/PR:L/UI:N/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 exploitPublished

Weakness, pattern, technique

CWE-428Unquoted Search Path or Element
T1574.009Path Interception by Unquoted Path

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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