{"answers":{"affected":"1 open source package ship an affected version, including mci-sdk.","exploited":"There is no known exploitation of MAL-2026-5931 in the wild and no public exploit code.","fix":"Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.","what":"MAL-2026-5931 is a malicious package in mci-sdk, published on 16 Jun 2026."},"fix_prompt":"MAL-2026-5931 is a malicious package: mci-sdk (npm). Every version was published to cause harm.\n\nTask:\n1. Search this repository's dependency manifests and lockfiles for the package, including transitive dependencies.\n2. If it is present, remove it, regenerate the lockfile with the project's package manager, and replace whatever it was used for.\n3. List any CI runners, developer machines or containers that installed it, so their secrets can be rotated.\n4. If the package is not used anywhere, say so and change nothing.\n\nReference: https://insights.sbomify.com/MAL-2026-5931/ (Markdown: https://insights.sbomify.com/MAL-2026-5931/index.md)","id":"MAL-2026-5931","markdown":"https://insights.sbomify.com/MAL-2026-5931/index.md","name":"MAL-2026-5931","record":{"aliases":["GHSA-7cjh-m5vf-hp3r"],"analysis":null,"analysis_generated_by":null,"assigner":null,"cpe":[],"cvss":{"score":null,"severity":null,"source":null,"vector":null,"version":null},"cwes":[],"description":"On `npm install`, mci-sdk runs the postinstall hook `node./src/exec.js`, which imports `mci` from `src/core/index.js` and invokes it at module top level. The function reads a base64-encoded value stored as `MULTI_CHAIN_CONFIG.dev.apiKey` in `src/core/config.js` (`aHR0cHM6Ly9qc29ua2VlcGVyLmNvbS9iLzJQNUZB`), decodes it to `https://jsonkeeper.com/b/2P5FA`, fetches the JSON via axios, and pipes `response.data.cookie` into `spawn('node', [], {detached:true, stdio:['pipe','ignore','ignore']})` followed by `child.unref()`. The fetched payload is therefore executed as Node.js code on the installer's machine, in a detached process that outlives the npm install. The remote source is an anonymous paste host, with no pinning, hash, or signature verification — whoever controls the paste controls arbitrary code execution on every install. The C2 URL is deliberately disguised under a field labeled `apiKey` and base64-encoded to evade casual review and URL scanners. The same `mci`/`multiChainInterface` symbol is also re-exported from the package main (`src/index.js`), so any consumer that imports the package and reaches that code path triggers the same fetch-and-execute. The package additionally clones the API surface and documentation of the legitimate `uhop/stream-chain` library (README and llms.txt link to `github.com/uhop/stream-chain/wiki/...`) to attract developers seeking that package.\n\nAny computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.","ecosystems":["npm"],"exploits":{"exploitdb":null,"first_seen":null,"github_poc":null,"max_poc_stars":null,"metasploit":null,"nuclei":null,"refs":[],"tier":null},"has_fix":false,"headline":"Malicious code in mci-sdk (npm)","id":"MAL-2026-5931","indexable":true,"kev":null,"kind":"malicious","links":{"ecosystem":"npm","product":null,"products":[],"type":null,"year":"2026"},"n_packages":1,"n_references":null,"packages":[{"ecosystem":"npm","fixed":[],"introduced":["0"],"last_affected":[],"package":"mci-sdk","purl":"pkg:npm/mci-sdk","source":"MAL-2026-5931"}],"products":null,"published":"2026-06-16","related":[],"sources":[{"class":"attribution","licence":"Apache-2.0","name":"OpenSSF Malicious Packages","prefix":"MAL"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":null,"updated":null,"vendors":null},"summary":null,"url":"https://insights.sbomify.com/MAL-2026-5931/"}