How severe is CVE-2021-25297?

CVE-2021-25297 has a CVSS score of 8.8/10, rated HIGH. Immediate patching is strongly recommended.

Which products are affected by CVE-2021-25297?

CVE-2021-25297 affects the following products: nagios nagios xi.

How do I patch CVE-2021-25297?

No patch has shipped for CVE-2021-25297 yet — track the nagios nagios xi advisory for a fixed release and apply the workarounds below in the meantime.

How do I detect CVE-2021-25297 across my infrastructure?

Inventory every nagios nagios xi deployment and check each version against the affected-products list above.

How do I mitigate CVE-2021-25297 if there is no patch (or I can't update yet)?

Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.

Is CVE-2021-25297 actively exploited in the wild?

Yes. There are 9 known exploit references for CVE-2021-25297, including 9 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2021-25297?

CVE-2021-25297 has an EPSS (Exploit Prediction Scoring System) score of 56.7%, placing it in the 99th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

Is CVE-2021-25297 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2021-25297 (Nagios XI OS Command Injection) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2022-01-18. CISA required all US federal civilian agencies to remediate this vulnerability by 2022-02-01. The required action was: Apply updates per vendor instructions. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

What type of vulnerability is CVE-2021-25297?

CVE-2021-25297 is classified as OS Command Injection (CWE-78). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

Which products and versions are affected by CVE-2021-25297?

CVE-2021-25297 affects nagios nagios xi. Check the affected-products list on this page against your deployed version to confirm exposure.

Is there exploit tooling available for CVE-2021-25297?

A Nuclei detection template exists for CVE-2021-25297, meaning automated scanners can fingerprint it. 2 Metasploit modules reference CVE-2021-25297, which lowers the barrier to weaponization. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2021-25297 published, and has it been updated?

CVE-2021-25297 was published on February 15, 2021 and was last updated on July 9, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🛡️

CISA KEV · ACTIVELY EXPLOITED

HIGH severity

CVE-2021-25297 — Nagios Xi

HIGH

CVE-2021-25297 is a high-severity (CVSS 8.8) OS Command Injection vulnerability in nagios nagios xi. It is in CISA's Known Exploited Vulnerabilities catalog (added 2022-01-18) — treat it as actively exploited and patch now. No vendor fix is recorded yet; mitigation options are listed below.

Nagios XI version xi-5.7.5 is affected by OS command injection. The vulnerability exists in the file /usr/local/nagiosxi/html/includes/configwizards/switch/switch.inc.php due to improper…

Published

Feb 15, 2021

Updated

Jul 9, 2026

Affected

1 product

Patched

See advisory

Exploits

9 known

Exploitation data as of Oct 22, 2026 · OSV.dev, NVD, CISA KEV, FIRST.org (EPSS)

Exploitation Status

Actively exploited in the wild

Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2022-01-18. Federal agencies were required to remediate by 2022-02-01.
A successful exploit gives an attacker total control of the affected component, not partial access.

Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2021-25297.

EPSS Exploitation Probability

via FIRST.org ↗

56.7%probability of exploitation in next 30 days

High Risk0.00%

Lower risk than most CVEs99th percentile — riskier than 99% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2021-25297 by exploitation likelihood (EPSS) against impact (CVSS). In the shaded patch-first corner (EPSS 50%+, CVSS 7.0+).

Where this sits among everything scored

Of 395,249 CVEs with a current EPSS score, this one falls in the 50–90% band (highlighted). Counts from FIRST.org, log-scaled.

Description

Nagios XI version xi-5.7.5 is affected by OS command injection. The vulnerability exists in the file /usr/local/nagiosxi/html/includes/configwizards/switch/switch.inc.php due to improper sanitization of authenticated user-controlled input by a single HTTP request, which can lead to OS command injection on the Nagios XI server.

Affected Products

1 product · 1 configurations

Application

nagios xinagios

≥ 5.5.6 && ≤ 5.7.5

range

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.