devplatform-react-mcpnpm
devplatform-react-mcp is a confirmed malicious npm package (MAL-2026-13502) that executes malicious code on install (malicious version 35.5.6). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in devplatform-react-mcp (npm)
What this malware does
[email protected] is a dropper disguised as a React MCP SDK. On require(), index.js loads helpers.js which assembles three Cloudflare Workers hostnames (oob-worker.cf99-9b3.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf102-baf.workers.dev) from small string fragments joined at runtime, downloads a platform-specific binary via https.get, writes it to /tmp/.cache<hex> or %TEMP%\dotnet_diag_<hex>.exe, chmods it 0755, and spawns it detached via /bin/sh -c or cmd /c start. A DNS-TXT fallback resolves further payload sources under sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, and net.dl.wel1.ru. A second dropper pipeline in lib/telemetry.js repeats the same primitives (base64 chunk assembly, fs["chmod"+"Sync"], cp.spawn("/bin/sh",["-c", filePath+" &"])) behind an 'analytics SDK' cover story. Identifier strings such as child_process and chmodSync are concatenated at runtime to evade static analysis. There is no native-build purpose; the package is a stub SDK whose only observable behavior on load is fetching and executing an opaque attacker-controlled binary on the installer's host.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Malicious packageFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for devplatform-react-mcp (version 35.5.6). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging devplatform-react-mcp across your stack and pipelines.
If you installed it — respond
Remove devplatform-react-mcp from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.
Did it already run?
If devplatform-react-mcp was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.
How O3 protects you
O3 blocks devplatform-react-mcp before install through its supply-chain scanner, and if it has already run, detects and severs the exfiltration or C2 callback at runtime through L7 egress monitoring and eBPF.
Frequently asked questions
Campaign
References
Credits
- Amazon Inspector · finder
Detect & block this
O3 blocks devplatform-react-mcp-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the malicious outbound activity and severs the channel.