CVE-2025-64996

Monitoring data exposure and tampering via world-writable files

Published Nov 18, 2025 · Updated Nov 18, 2025

Incorrect permissions in the Checkmk mk_inotify plugin allow local users to read or alter monitoring data through its output files. The plugin calls os.umask(0), causing files under /var/lib/check_mk_agent to be created world-readable and world-writable with mode 0666. Exposure requires the inotify agent plugin to have been deployed; any local account can then inspect or manipulate its generated data.

CVSS severity4.8
Medium
EPSS probability0.10%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect permissions in the Checkmk mk_inotify plugin allow local users to read or alter monitoring data through its output files. The plugin calls os.umask(0), causing files under /var/lib/check_mk_agent to be created world-readable and world-writable with mode 0666. Exposure requires the inotify agent plugin to have been deployed; any local account can then inspect or manipulate its generated data.

The record

CVE
CVE-2025-64996
Published
Nov 18, 2025
Updated
Nov 18, 2025
Vendor
Checkmk GmbH
Product
Checkmk
Classifications
CWE-732, T1565.001, T1005
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 18, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 18, 2025Record 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=2.1.0
  2. Affected versionversion=2.2.0
  3. Affected versionversion=2.3.0 <2.3.0p41
  4. Affected versionversion=2.4.0 <2.4.0p16

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Checkmk GmbH · Checkmkversion=2.1.0; version=2.2.0; version=2.3.0 <2.3.0p41; version=2.4.0 <2.4.0p16

Published CVSS scores

4.8Checkmk GmbHCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:L/SI:N/SA:N
4.4NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-732Incorrect Permission Assignment for Critical Resource
T1565.001Stored Data Manipulation
T1005Data from Local System

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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