CVE-2023-39107Public exploit

Root-owned file overwrite via writable log directory

Published Aug 4, 2023 · Updated Oct 17, 2024

Arbitrary file overwrite in NoMachine Free Edition and Enterprise Client on macOS before 8.8.1 allows local users to overwrite root-owned files. The application writes logs in /Library/Application Support/NoMachine/var/log despite permissions allowing local users to replace a log with a hardlink. A local user must create the hardlink before a privileged log write, which can corrupt the linked file and interrupt services that depend on it.

CVSS severity9.1
Critical
EPSS probability1.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Arbitrary file overwrite in NoMachine Free Edition and Enterprise Client on macOS before 8.8.1 allows local users to overwrite root-owned files. The application writes logs in /Library/Application Support/NoMachine/var/log despite permissions allowing local users to replace a log with a hardlink. A local user must create the hardlink before a privileged log write, which can corrupt the linked file and interrupt services that depend on it.

The record

CVE
CVE-2023-39107
Published
Aug 4, 2023
Updated
Oct 17, 2024
Vendor
NoMachine
Product
NoMachine Free Edition
Classifications
CWE-59, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 4, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 17, 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=0 <v8.8.1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

NoMachine · NoMachine Free Editionversion=0 <v8.8.1
NoMachine · NoMachine Enterprise Clientversion=0 <v8.8.1

Published CVSS scores

9.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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.

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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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-59Improper Link Resolution Before File Access ('Link Following')
T1068Exploitation for Privilege Escalation

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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