CVE-2021-40343Public exploit

Root privilege escalation via writable migration script

Published Oct 26, 2021 · Updated Aug 4, 2024

Local privilege escalation in Nagios XI 5.8.3 through 5.8.5 allows local users with nagios access to execute commands as root. The passwordless root migration path copies and runs nagios_unbundler.py even though the nagios account owns and can modify that script. Exploitation requires control of the nagios account and winning a file-placement race so migration reaches the altered script, yielding a root shell.

CVSS severity7.8
High
EPSS probability0.68%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Local privilege escalation in Nagios XI 5.8.3 through 5.8.5 allows local users with nagios access to execute commands as root. The passwordless root migration path copies and runs nagios_unbundler.py even though the nagios account owns and can modify that script. Exploitation requires control of the nagios account and winning a file-placement race so migration reaches the altered script, yielding a root shell.

The record

CVE
CVE-2021-40343
Published
Oct 26, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-732, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 26, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.8NVDCVSS: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.

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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-732Incorrect Permission Assignment for Critical Resource
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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