CVEs-PoC/2021/CVE-2021-42387.md

### [CVE-2021-42387](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-42387)
![](https://img.shields.io/static/v1?label=Product&message=clickhouse&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=unspecified%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=CWE-125&color=brightgreen)

### Description

Heap out-of-bounds read in Clickhouse's LZ4 compression codec when parsing a malicious query. As part of the LZ4::decompressImpl() loop, a 16-bit unsigned user-supplied value ('offset') is read from the compressed data. The offset is later used in the length of a copy operation, without checking the upper bounds of the source of the copy operation.

### POC

#### Reference
- https://jfrog.com/blog/7-rce-and-dos-vulnerabilities-found-in-clickhouse-dbms

#### Github
No PoCs found on GitHub currently.