# MAL-2026-5434: Malicious code in ac_calendar_ts (npm)


- **Type:** Malicious package
- **Package:** `ac_calendar_ts` (npm)
- **Published:** 9 Jun 2026
- **Also known as:** GHSA-xgwp-29j2-jxj3

## What is MAL-2026-5434?

MAL-2026-5434 is a malicious package in ac_calendar_ts, published on 9 Jun 2026. 

### Official description

On `npm install`, the package's `canary.js` postinstall script issues an HTTP GET to http://157.230.17.236/dc carrying the installer's `os.hostname()`, package name, version, a fixed nonce, and a phase identifier. The destination is a hardcoded bare IP over plain HTTP with no opt-in, no documented purpose, and no relationship to any declared package functionality. The package describes itself as a 'dependency-confusion canary,' which matches the pattern used to enumerate internal networks that resolved a public name — the installer's host identifier is exfiltrated to an external operator without consent. The version number (99.99.100) is also consistent with dependency-confusion targeting, in which an attacker publishes an artificially high version under a name expected to exist in a private registry.

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-2026-5434?

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-2026-5434 is a malicious package: ac_calendar_ts (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-2026-5434/ (Markdown: https://insights.sbomify.com/MAL-2026-5434/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-5434

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-5434/
Summaries are generated and may contain mistakes; the official description above is the record.