Command Injection Vulnerability (CVE-2021-21315)

What is affected, what to do

The System Information Library for Node.JS (npm package "systeminformation") is an open source collection of functions to retrieve detailed hardware, system and OS information. In systeminformation before version 5.3.1 there is a command injection vulnerability.

The vulnerability is being actively exploited; treat it as a priority. Update Sebhildebrandt Systeminformation to version 5.3.1. Immediate actions, mitigation and detection rules are in the runbook below.

Affected

• Sebhildebrandt Systeminformation lt *..5.3.1

Fixed in

• Sebhildebrandt Systeminformation 5.3.1

Not sure whether and how you are affected? Ask a question about this vulnerability

Metrics

Response and mitigation

1. 01

   Runbook step 1

   Immediate response (0-24 h)

   • Inventory: Search every Node.js repository, build artefact and container image for systeminformation, including transitive use: npm ls systeminformation --all or grep -r '"systeminformation"' package-lock.json yarn.lock. Use SBOM tooling (Syft, Trivy, Dependency-Track) to flag all versions below 5.3.1.
   • Patch: Upgrade to at least systeminformation@5.3.1, ideally the current 5.x release (later versions close further command-injection variants in the same function family). For transitive dependencies, pin via overrides (npm) or resolutions (Yarn) in package.json, regenerate the lockfile, rebuild and redeploy container images.
   • Exposed apps first: Prioritise internet- or customer-facing services (monitoring dashboards, admin UIs, status pages, Electron/Cordova apps) that pass user input into si.inetLatency(), si.inetChecksite(), si.services() or si.processLoad(). If you cannot upgrade today, disable those endpoints or put them behind VPN/IP allowlisting.
   • Apache Cordova 10.0.0: Check build environments and CI runners running Cordova 10.0.0; look up the fixed Cordova release in the vendor advisory and upgrade so the patched dependency is pulled in.
   • Compromise assessment: On hosts that ran a vulnerable version, review the Node process's child-process history for shell spawns (see Detection rules). On any hit, isolate the host and rotate secrets reachable from the process context (environment variables, .env files, cloud tokens, database credentials).
2. 02

   Runbook step 2

   Mitigation layers

   • Application code (input validation): Enforce strict type checks before calling the affected functions — accept strings only, reject arrays, e.g. if (typeof name !== 'string') return res.status(400).end();. The flaw exists because arrays bypass the library's internal string sanitisation; add an allowlist regex (e.g. ^[a-zA-Z0-9._-]+$ for service names) on top.
   • Framework configuration: In Express, switch off the extended query parser (app.set('query parser', 'simple')) so name[]=… is never turned into an array; restrict body parsers to flat structures likewise.
   • WAF/reverse proxy: Block requests to the affected paths where parameters use array syntax ([], %5B%5D) combined with shell metacharacters (;, |, &, `, $(, %24%28). For ModSecurity/OWASP CRS, run rule group 932 (RCE/Unix command injection) in blocking mode for these apps.
   • Endpoint/container hardening: Never run Node services as root; use distroless or minimal images without curl, wget, nc, bash; apply a seccomp/AppArmor profile limiting execve from the Node process to required binaries; mount the root filesystem read-only.
   • Network segmentation: Restrict application-server egress to required destinations to stop payload staging and reverse shells.
   • Supply chain: Make npm audit --audit-level=high or Dependabot/Renovate a blocking CI gate so vulnerable versions cannot slip back into builds.
3. 03

   Runbook step 3

   Detection rules

   • EDR/Sysmon EID 1 (Windows): Node spawning shells with suspicious arguments. KQL: DeviceProcessEvents | where InitiatingProcessFileName =~ "node.exe" and FileName in~ ("cmd.exe","powershell.exe") and ProcessCommandLine has_any ("curl","Invoke-WebRequest","certutil","whoami").
   • Linux auditd/EDR: execve events with parent node, child /bin/sh -c, followed by curl, wget, nc, bash -i or python -c. Sigma shape: ParentImage|endswith: '/node' AND Image|endswith: ['/curl','/wget','/nc','/bash'] AND CommandLine|contains: ['http','/dev/tcp','base64'].
   • Web server/proxy access logs: Array parameters carrying metacharacters, regex [?&][a-zA-Z_]+(\[\]|%5B%5D)=[^&]*(%3B|%7C|%60|%24%28|;|\||\$\(). SPL: index=web uri_query="*%5B%5D=*" (uri_query="*%3B*" OR uri_query="*%7C*" OR uri_query="*%24%28*").
   • Network telemetry (Zeek/Suricata): New outbound connections from app servers to unfamiliar destinations shortly after HTTP requests to monitoring endpoints; Suricata rule on http.uri with content:"%5B%5D="; pcre:"/(%3B|%7C|%60|%24%28)/";.
   • Vulnerability scanning: Feed SCA findings (Trivy, Snyk, Dependency-Track) for CVE-2021-21315 into the SIEM as high-priority and correlate them with runtime assets.

Detection rules

No NEOSEC detection rule is available for this vulnerability yet.

Classification under NIS2 and CRA

Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

NIS2

NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

Read in glossary

Actively exploited: treat the vulnerability as a priority in vulnerability handling under Art. 21(2)(e) NIS2. If it is exploited in your environment, check the reporting obligation under Art. 23 (early warning within 24 hours).

CRA

The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

Read in glossary

Since 11.09.2026, manufacturers of affected products with digital elements must report actively exploited vulnerabilities under Art. 14 CRA, with an early warning within 24 hours via ENISA's single reporting platform.

ISO/IEC 27001

ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

Read in glossary

Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

Description

The System Information Library for Node.JS (npm package "systeminformation") is an open source collection of functions to retrieve detailed hardware, system and OS information. In systeminformation before version 5.3.1 there is a command injection vulnerability. Problem was fixed in version 5.3.1. As a workaround instead of upgrading, be sure to check or sanitize service parameters that are passed to si.inetLatency(), si.inetChecksite(), si.services(), si.processLoad() ... do only allow strings, reject any arrays. String sanitation works as expected.

Source: NVD (NIST), OSV (Open Source Vulnerabilities), cvelistv5, CISA KEV Catalog

Vendors and products

• Apache Software Foundation Apache Cordova Android
• Sebhildebrandt Systeminformation
• Systeminformation systeminformation

Weakness classes (CWE)

• CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

  Base

  The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.

  Entry at MITRE CWE-78

References & sources

• github.comsebhildebrandt/systeminformation/security/advisories/GHSA-2m8v-…web, x_refsource_CONFIRM, Third-party advisory
• NVD (NIST)vuln/detail/CVE-2021-21315advisory
• github.comsebhildebrandt/systeminformation/commit/07daa05fb06f24f96297aba…web, x_refsource_MISC, Patch
• github.comsebhildebrandt/systeminformationpackage
• lists.apache.org[cordova-issues] 20210224 [GitHub] [cordova-cli] iva2k opened a new issue #549: update systeminformation package to >=5.3.1web, Mailing list, x_refsource_MLIST, Issue tracking, Mailing list
• lists.apache.orgthread.html/r8afea9a83ed568f2647cccc6d8d06126f9815715ddf9a4d479…web
• security.netapp.comadvisory/ntap-20210312-0007web
• cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2021-21315web, government-resource, US government resource
• npmjs.compackage/systeminformationweb, x_refsource_MISC, Product
• security.netapp.comadvisory/ntap-20210312-0007x_refsource_CONFIRM, Third-party advisory