CVE-2025-65000Network attack vector

Alert-handler execution via exposed SSH private keys

Published Dec 18, 2025 · Updated Dec 18, 2025

Information disclosure in Checkmk 2.3.0 and 2.4.0 before 2.4.0p18 allows remote authenticated users to obtain SSH private keys. The Remote alert handlers (Linux) rule embeds its SSH private key in the rule page's HTML source instead of removing the secret before rendering. A configured rule and low-privileged Checkmk account are required; the key can trigger only the handlers fixed in each affected host's authorized_keys file.

CVSS severity2.3
Low
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

Information disclosure in Checkmk 2.3.0 and 2.4.0 before 2.4.0p18 allows remote authenticated users to obtain SSH private keys. The Remote alert handlers (Linux) rule embeds its SSH private key in the rule page's HTML source instead of removing the secret before rendering. A configured rule and low-privileged Checkmk account are required; the key can trigger only the handlers fixed in each affected host's authorized_keys file.

The record

CVE
CVE-2025-65000
Published
Dec 18, 2025
Updated
Dec 18, 2025
Vendor
Checkmk GmbH
Product
Checkmk
Classifications
CWE-212, T1552.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 18, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 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=2.3.0
  2. Affected versionversion=2.4.0 <2.4.0p18

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Checkmk GmbH · Checkmkversion=2.3.0; version=2.4.0 <2.4.0p18

Published CVSS scores

5.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
2.3Checkmk GmbHCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:L/SA:L

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)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-212Improper Removal of Sensitive Information Before Storage or Transfer
T1552.004Unsecured Credentials: Private Keys

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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