CVE-2020-6582Public exploitNetwork attack vector

Remote denial of service via negative packet length

Published Mar 16, 2020 · Updated Aug 4, 2024

Heap-based buffer overflow in Nagios NRPE 3.2.1 allows remote attackers to cause a service crash via a crafted NRPE v3 packet. The read_packet path accepts a signed negative buffer_length, reduces the allocation to zero, and passes that value to recvall, where bzero converts it to a huge unsigned length and overwrites heap memory. An attacker only needs network access to the NRPE service; the demonstrated consequence is a daemon-thread crash and service interruption, with no reported confidentiality or integrity impact.

CVSS severity7.5
High
EPSS probability3.97%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in Nagios NRPE 3.2.1 allows remote attackers to cause a service crash via a crafted NRPE v3 packet. The read_packet path accepts a signed negative buffer_length, reduces the allocation to zero, and passes that value to recvall, where bzero converts it to a huge unsigned length and overwrites heap memory. An attacker only needs network access to the NRPE service; the demonstrated consequence is a daemon-thread crash and service interruption, with no reported confidentiality or integrity impact.

The record

CVE
CVE-2020-6582
Published
Mar 16, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787, CWE-681, T1499.004
Attack vector
network
Privileges
unauthenticated

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 privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.0NVDAV:N/AC:L/Au:N/C:N/I:N/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.

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
CWE-681Incorrect Conversion between Numeric Types
T1499.004Application or System Exploitation

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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