How severe is CVE-2020-36856?

CVE-2020-36856 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2020-36856 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-36856?

CVE-2020-36856 affects Nagios Nagios Xi. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-36856?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2020-36856 have an EU (EUVD) identifier?

Yes. CVE-2020-36856 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2020-30816.

When was CVE-2020-36856 published?

CVE-2020-36856 was published on 2025-10-30 and last updated on 2026-06-17.

CVE-2020-36856

CVE-2020-36856 is a high-severity vulnerability in Nagios Nagios Xi with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-78.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v4: 9.4
EPSS exploit prediction: 2% (81st percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2020-30816
Weakness: CWE-78
Affected product: Nagios Nagios Xi
Published: 2025-10-30
Last modified: 2026-06-17

Description

Nagios XI versions prior to 5.6.14 contain an authenticated remote command execution vulnerability in the CCM command_test.php script. Insufficient validation of the `address` parameter allows an authenticated user with access to the Core Config Manager to inject shell metacharacters that are incorporated into backend command invocations. Successful exploitation enables arbitrary command execution with the privileges of the Nagios XI web application user and may be leveraged to execute commands on the underlying XI host, modify system configuration, or fully compromise the host.

Frequently asked questions

What is CVE-2020-36856?: Nagios XI versions prior to 5.6.14 contain an authenticated remote command execution vulnerability in the CCM command_test.php script. Insufficient validation of the `address` parameter allows an authenticated user with access to the Core Config Manager to inject shell metacharacters that are incorporated into backend command invocations. Successful exploitation enables arbitrary command execution with the privileges of the Nagios XI web application user and may be leveraged to execute commands on the underlying XI host, modify system configuration, or fully compromise the host.
How severe is CVE-2020-36856?: CVE-2020-36856 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2020-36856 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-36856?: CVE-2020-36856 affects Nagios Nagios Xi. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-36856?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2020-36856 have an EU (EUVD) identifier?: Yes. CVE-2020-36856 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2020-30816.
When was CVE-2020-36856 published?: CVE-2020-36856 was published on 2025-10-30 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:nagios:nagios_xi:*:*:*:*:*:*:*:*

More vulnerabilities in Nagios Nagios Xi

CVE-2024-14003 — Critical (CVSS 9.8): Nagios XI versions prior to 2024R1.2 are vulnerable to remote code execution (RCE) through its NRDP (Nagios Remote…
CVE-2024-13999 — Critical (CVSS 9.8): Nagios XI versions prior to 2024R1.1.3, under certain circumstances, disclose the server's Active Directory (AD) or…
CVE-2024-13996 — Critical (CVSS 9.8): Nagios XI versions prior to 2024R1.1.3 did not invalidate all other active sessions for a user when that user's…
CVE-2024-13994 — Critical (CVSS 9.8): Nagios XI versions prior to 2024R1.1.2 contain a missing authorization control when the 'Allow Insecure Logins'…
CVE-2012-10063 — Critical (CVSS 9.8): Nagios XI versions prior to 2012R1.3 contain a SQL injection vulnerability in the legacy Core Configuration Manager…
CVE-2024-33775 — Critical (CVSS 9.8): An issue with the Autodiscover component in Nagios XI 2024R1.01 allows a remote attacker to escalate privileges via a…

All CVEs affecting Nagios Nagios Xi →

Other CWE-78 (OS Command Injection) vulnerabilities

CVE-2026-56004 — Critical (CVSS 10.0): A shellcode injection in the mercurial handler of the obs tar_scm source service before version 0.12.4 could be used by…
CVE-2026-56415 — Critical (CVSS 10.0): Storage Concentrator (SC & SCVM) contains a command injection vulnerability within the debug.pl script that is…
CVE-2026-56413 — Critical (CVSS 10.0): Storage Concentrator (SC & SCVM) contains a command injection vulnerability in the ms_service.pl service, which listens…
CVE-2026-49869 — Critical (CVSS 10.0): Kestra is an open-source, event-driven orchestration platform. Prior to 1.0.45 and 1.3.21, AuthenticationFilter in…
CVE-2026-49261 — Critical (CVSS 10.0): MariaDB server is a community developed fork of MySQL server. Versions 10.6.1 through 10.6.26, 10.11.1 through…
CVE-2026-10520 — Critical (CVSS 10.0): An OS Command Injection vulnerability in Ivanti Sentry before the R10.5.2, R10.6.2 and R10.7.1 versions allows a…

Browse all CWE-78 (OS Command Injection) vulnerabilities →