CriticalCVE-2025-11953

    React Native Community CLI OS Command Injection Vulnerability (CVE-2025-11953)

    Published In CISA KEV since Sources: SingCERT, pwn.watch, CVE.org, OSV

    What is affected, what to do

    The Metro Development Server, which is opened by the React Native Community CLI, binds to external interfaces by default. The server exposes an endpoint that is vulnerable to OS command injection.

    The vulnerability is being actively exploited; treat it as a priority. Update @react-native-community/cli-server-api to version 20.0.0. Immediate actions, mitigation and detection rules are in the runbook below.

    Affected
    • @react-native-community/cli-server-api lt 4.8.0..20.0.0
    Fixed in
    • @react-native-community/cli-server-api 20.0.0

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

    Metrics

    9.8

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: NVD, CVSS v3

    9.8

    CVSS v3

    Severity Critical on the scale from 0 to 10.

    Source: SingCERT, pwn.watch, CVE.org, OSV

    94.0 %

    EPSS score

    High — model estimates ≥ 50% chance of real-world exploitation within 30 days.

    Source: FIRST EPSS, percentile 99.85

    Show all metrics
    Severity
    Critical
    Priority (0–325)

    The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?

    Read in glossary
    240.59 Methodology
    Exploit maturity

    An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.

    Read in glossary
    actively exploitedSource: VulnCheck KEV (opens in a new tab) How we classify
    XIEM Effective CVSS

    XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.

    Read in glossary
    9.8 Methodology
    CVSS v3

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    9.8
    EPSS score

    The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.

    Read in glossary
    94.0 %
    High — model estimates ≥ 50% chance of real-world exploitation within 30 days.
    EPSS percentile

    The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.

    Read in glossary
    99.85
    Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
    KEV status

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    Actively exploited
    Published
    In CISA KEV since

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    CISA assessment (SSVC)
    Exploitation: active · automatable · Technical impact: total
    Source: CISA Vulnrichment, as of 6 February 2026
    CWE

    CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.

    Read in glossary
    CWE-78

    Response and mitigation

    Why act now?

    Prioritisation rationale

    The flaw is network-reachable without authentication or user interaction. Metro also binds to all interfaces by default, so any developer laptop on a shared or public network is directly exposed. Attackers scan for open port 8081 to drop payloads onto developer and build systems. These are high-value footholds because they hold source code, signing keys and pipeline credentials, which opens the door to supply-chain compromise. Exploitation likelihood is among the very highest of any CVE, though CISA does not flag known ransomware use. Organisations with in-house React Native development, or contractors with internal network access, should treat this as critical. Handle Windows hosts and externally reachable CI runners first, and check production-only environments without Metro last.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Patch now: Upgrade @react-native-community/cli-server-api to 20.0.0 or later, or @react-native-community/cli on the 19.x line to 19.1.2 or later. The affected range runs from 4.8.0 up to 20.0.0, including the 19.0.0-alpha.0 and 20.0.0-alpha.0 prereleases. Reinstall node_modules and commit the lockfile so transitive dependencies actually move. Verify with npm ls @react-native-community/cli-server-api or yarn why @react-native-community/cli-server-api.
      • Inventory developer endpoints and build agents: Find every host running the Metro Development Server (default TCP 8081). That includes developer laptops, CI/CD runners, macOS build hosts and test VMs. An internal sweep for open 8081/TCP gives a fast first picture.
      • Restrict the bind address immediately: Until patched, start Metro bound to loopback only with npx react-native start --host 127.0.0.1. Kill any Metro processes currently listening on external interfaces.
      • Prioritise Windows hosts: On Windows the flaw allows arbitrary shell commands with fully attacker-controlled arguments. Patch or network-isolate these first.
      • Assume compromise where exposed: Treat any host where Metro was reachable from untrusted networks (guest Wi-Fi, home office without VPN, public cloud VM) as potentially compromised. Run EDR triage and rotate locally stored secrets: Git tokens, npm tokens, signing keys, cloud credentials and .env files.

    2. Runbook step 2

      Mitigation layers

      • Network segmentation: Block inbound 8081/TCP to developer segments and CI runners at both perimeter and internal firewalls. Metro normally needs only loopback or a USB/ADB tunnel (adb reverse tcp:8081 tcp:8081), not LAN exposure.
      • Host firewall: Push a Windows Defender Firewall rule via GPO or Intune that denies inbound connections to node.exe from non-loopback sources. On macOS use the Application Firewall or pf. On Linux use an nftables drop on tcp dport 8081 except from lo.
      • IPS/NIDS rule: Write a Suricata/Snort signature for HTTP POST to /open-url on port 8081 from non-loopback sources. Drop and alert when the JSON body's url field is not a plain http(s):// URL, for example when it contains cmd, powershell, file: or executable paths.
      • Endpoint hardening: Set EDR or ASR rules that block, or at least alert on, node.exe spawning cmd.exe, powershell.exe, mshta.exe, rundll32.exe or certutil.exe outside known build scripts. On Linux and macOS, apply the same logic to node spawning sh, bash, curl or wget.
      • Supply chain and configuration management: Pin minimum CLI versions via npm overrides or Yarn resolutions. Gate pipelines on dependency scanning (npm audit, Dependabot, Renovate) and fail builds that carry vulnerable versions.
      • Least privilege: Don't run development environments with local admin rights. Keep CI runners ephemeral and free of persistent production credentials.

    3. Runbook step 3

      Detection rules

      • Network telemetry (Zeek/Suricata): Flag HTTP POST to /open-url on port 8081 from external or non-loopback IPs. Zeek example: http.log | where method=="POST" and uri=="/open-url" and id.resp_p==8081 and id.orig_h!="127.0.0.1".
      • Process ancestry (Sysmon EID 1 / Windows Security 4688): Look for node.exe parenting shells or LOLBins. KQL: DeviceProcessEvents | where InitiatingProcessFileName =~ "node.exe" and FileName in~ ("cmd.exe","powershell.exe","pwsh.exe","mshta.exe","rundll32.exe","certutil.exe","bitsadmin.exe"). Baseline the results against legitimate build tooling.
      • Sigma shape: Use logsource: process_creation with ParentImage|endswith: '\node.exe', Image|endswith: ['\cmd.exe','\powershell.exe'] and ParentCommandLine|contains: 'react-native' or 'metro'. Set level high, especially when it correlates with an inbound connection on 8081 (Sysmon EID 3).
      • Linux/macOS (auditd/EDR): Watch for execve events whose ppid is a node process with react-native start in its command line and whose child is sh, bash, curl, wget, python or osascript.
      • Follow-on activity: Watch for new outbound connections from developer hosts to unknown domains shortly after Metro access. Also look for file writes to %TEMP% or %APPDATA% by shell children of node.exe (Sysmon EID 11) and Defender exclusions added via PowerShell.

    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 Metro Development Server, which is opened by the React Native Community CLI, binds to external interfaces by default. The server exposes an endpoint that is vulnerable to OS command injection. This allows unauthenticated network attackers to send a POST request to the server and run arbitrary executables. On Windows, the attackers can also execute arbitrary shell commands with fully controlled arguments.

    Source: CSA/SingCERT, pwn.watch, NVD (NIST), cvelistv5, CISA KEV Catalog, CVE.org (MITRE), OSV (Open Source Vulnerabilities)

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    —@react-native-community/cli-server-api
    • 4.8.0 – < 20.0.0
    • 20.0.0
    react-native-communityreact_native_community_cli
    • 19.0.0 – < 19.1.2
    • 20.0.0
    • 18.0.0
    • 19.1.2
    • —
    • —
    npm@react-native-community/cli
    • 18.0.0
    • 19.0.0-alpha.0
    • 20.0.0-alpha.0
    • —
    • —
    • —
    npm@react-native-community/cli-server-api
    • 18.0.0
    • 19.0.0-alpha.0
    • 20.0.0-alpha.0
    • —
    • —
    • —

    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

    Public exploit references

    Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.

    Public exploit references
    CISA KEV CatalogCISA Known Exploited Vulnerability (opens in a new tab)cisa.govactively exploited
    Reference tagged as exploitvulncheck.com (opens in a new tab)PoC (publicly reported)reported, not verified—
    PoC-in-GitHub (nomi-sec)CVE-2025-11953-POC- (opens in a new tab)github.comPoC (publicly reported)reported, not verified

    References & sources

    • NVD (NIST)NVD: CVE-2025-11953advisory, pwn-watch
    • github.comreact-native-community/cli/issues/2733web
    • github.comreact-native-community/cli/pull/1615web
    • github.comReact Native Community CLI — CVE-2025-11953web, Patch, Patch, pwn-watch
    • github.comreact-native-community/cli/commit/5a792169d9883e0b0fb1ddf1ea467…web
    • github.comreact-native-community/cli/commit/9e1fa8cc633e5dcf32244ffa60a87…web
    • github.comreact-native-community/cli/commit/a8293dc29425f56249753507bc24d…web
    • github.comreact-native-community/clipackage
    • github.comreact-native-community/cli/releases/tag/v20.0.0web
    • github.comreact-native-community/cli?tab=readme-ov-fileweb
    • jfrog.comblog/cve-2025-11953-critical-react-native-community-cli-vulnera…web, Technical description, Exploit, Mitigation, Third-party advisory
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2025-11953web, government-resource, US government resource
    • vulncheck.comblog/metro4shell_eitwweb, Third-party advisory, Exploit, Third-party advisory
    • x.comSzymonRybczak/status/1986199665000566848web, Third-party advisory
    • x.comszymonrybczak/status/1986199665000566848?s=46web
    • x.comthymikee/status/1986770875954475375web, Third-party advisory
    • pwn.watchpwn.watch: React Native Community CLI: React Native Community CLI OS Command Injection Vulnerabilitypwn-watch
    • cisa.govCISA Known Exploited Vulnerabilities Catalogpwn-watch
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