apache-druid-security SKILL.md skillA
apache-druid-security from cxcscmu/skilllearnbench is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add cxcscmu/skilllearnbench/apache-druid-security@git:20260424.d50cf5aPins git:20260424.d50cf5a in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- cxcscmu/skilllearnbench
- Path
skills/b1-one-shot-claude-sonnet-4-6/fix-security-bug/apache-druid-security/SKILL.md- Versions recorded
- 1
- Latest version
- git:20260424.d50cf5a, committed Apr 24, 2026
- Size
- 3,872 bytes
- Repository stars
- 91
- License
- MIT
Security patching for Apache Druid - covers JavaScript execution vulnerabilities, sampler endpoint protection, and filter validation patterns.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Apache Druid Security Patching
## Overview
Apache Druid is a real-time analytics database. Key security concern: JavaScript execution via
filter/transform specs in ingestion tasks and the sampler endpoint.
## CVE-2021-25646 - JavaScript Filter RCE
### Vulnerability Mechanism
- `JavaScriptDimFilter` uses `@JacksonInject JavaScriptConfig config` to get JavaScript enabled status
- `@JacksonInject` with default `value=""` allows Jackson to fall back to JSON input when the
injectable value isn't found or when `useInput=OptBoolean.DEFAULT`
- Exploit: Send `"": {"enabled": true}` in the filter JSON to inject a permissive `JavaScriptConfig`
- This bypasses the server-level `druid.javascript.enabled=false` setting
- The Rhino JS engine has no `ClassShutter` → full Java class access → `Runtime.exec()` possible
### Affected Files
- `processing/src/main/java/org/apache/druid/query/filter/JavaScriptDimFilter.java`
- `indexing-service/src/main/java/org/apache/druid/indexing/overlord/sampler/InputSourceSampler.java`
- `core/src/main/java/org/apache/druid/js/JavaScriptConfig.java`
### Fix 1: Block JSON Override of @JacksonInject (Root Cause)
```java
…Read the whole file at its exact version.
How to install
mdr add cxcscmu/skilllearnbench/apache-druid-security@sha256:a6f2a2d94e934138The line at the top of this page pins the label git:20260424.d50cf5a, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_ce5lhsijgcmre3cr)
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Versions
The registry has recorded 1 version of this file, committed on Apr 24, 2026.
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (3872 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
cxcscmu/skilllearnbench · 91 stars · license MIT · pushed 2026-10-02 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_ce5lhsijgcmre3cr GET https://markdownregistry.com/api/v1/resolve?ref=cxcscmu/skilllearnbench/apache-druid-security GET https://markdownregistry.com/api/v1/blob/a6f2a2d94e93413889e527ce5806e0eaec2fe43f979921ff69b800555fdb0a40
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.