CVE-2020-6581Public exploitNetwork attack vector

Command injection via malformed metacharacter parsing

Published Mar 16, 2020 · Updated Aug 4, 2024

Insufficient filtering in Nagios NRPE 3.2.1 allows attackers to execute commands through crafted plugin arguments. The nasty_metachars configuration parser treats escape sequences such as \n as separate backslash and n characters, allowing newline metacharacters to bypass filtering before arguments reach monitoring scripts. Exploitation requires command-line parameter support and dont_blame_nrpe enabled; successful execution runs with the NRPE service account privileges.

CVSS severity7.3
High
EPSS probability1.61%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Insufficient filtering in Nagios NRPE 3.2.1 allows attackers to execute commands through crafted plugin arguments. The nasty_metachars configuration parser treats escape sequences such as \n as separate backslash and n characters, allowing newline metacharacters to bypass filtering before arguments reach monitoring scripts. Exploitation requires command-line parameter support and dont_blame_nrpe enabled; successful execution runs with the NRPE service account privileges.

The record

CVE
CVE-2020-6581
Published
Mar 16, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1059.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 16, 2020CVE 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 vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.3NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
3.7NVDAV:L/AC:H/Au:N/C:P/I:P/A:P

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 exploitPublished

Weakness, pattern, technique

T1059.004Command and Scripting Interpreter: Unix Shell

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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