# MAL-2026-4420: Malicious code in @polka-ui/loader (npm)


- **Type:** Malicious package
- **Package:** `@polka-ui/loader` (npm)
- **Published:** 25 May 2026
- **Also known as:** GHSA-j263-hx4f-ph92

## What is MAL-2026-4420?

MAL-2026-4420 is a malicious package in @polka-ui/loader, published on 25 May 2026. 

### Official description

On `npm install`, scripts/postinstall.js downloads a per-OS payload from https://oob.moika.tech/payload/{linux|mac|win}, writes it to /tmp/._polka-ui_init.sh (or.bat), chmods 0755, and spawns it via /bin/sh or cmd.exe with no integrity verification. The same script enumerates process.env for credential-shaped keys (npm_token, github_token, aws_access_key_id, aws_secret_access_key, aws_session_token, artifactory_token, nexus_token, node_auth_token, npm_config__auth), reads the first 15 lines of ~/.npmrc, /etc/npmrc,./.npmrc, and../.npmrc, and POSTs a JSON report containing hostname, username, cwd, PATH, the harvested env values, npmrc contents, and npm registry config to https://oob.moika.tech/report with an X-Secret header. The package self-describes as a dependency-confusion PoC under the @polka-ui scope; regardless of stated intent, any installer who resolves this from public npm receives full install-time RCE and credential exfiltration.

Any 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.

## What should I do about MAL-2026-4420?

Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.

## Fix prompt for AI coding agents

```text
MAL-2026-4420 is a malicious package: @polka-ui/loader (npm). Every version was published to cause harm.

Task:
1. Search this repository's dependency manifests and lockfiles for the package, including transitive dependencies.
2. If it is present, remove it, regenerate the lockfile with the project's package manager, and replace whatever it was used for.
3. List any CI runners, developer machines or containers that installed it, so their secrets can be rotated.
4. If the package is not used anywhere, say so and change nothing.

Reference: https://insights.sbomify.com/MAL-2026-4420/ (Markdown: https://insights.sbomify.com/MAL-2026-4420/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-4420

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-4420/
Summaries are generated and may contain mistakes; the official description above is the record.