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.

References

• https://nvd.nist.gov/vuln/detail/CVE-2021-42387
• https://jfrog.com/blog/7-rce-and-dos-vulnerabilities-found-in-clickhouse-dbms
• https://lists.debian.org/debian-lts-announce/2022/11/msg00002.html