CVE-2022-29240 – Uninitialized memory read in LZ4 decompression leads to authentication bypass in Scylla

https://notcve.org/view.php?id=CVE-2022-29240

Scylla is a real-time big data database that is API-compatible with Apache Cassandra and Amazon DynamoDB. When decompressing CQL frame received from user, Scylla assumes that user-provided uncompressed length is correct. If user provides fake length, that is greater than the real one, part of decompression buffer won't be overwritten, and will be left uninitialized. This can be exploited in several ways, depending on the privileges of the user. 1. The main exploit is that an attacker with access to CQL port, but no user account, can bypass authentication, but only if there are other legitimate clients making connections to the cluster, and they use LZ4. 2. • https://github.com/scylladb/scylla/security/advisories/GHSA-25pq-rrqm-6fmr https://github.com/scylladb/scylladb/commit/1c2eef384da439b0457b6d71c7e37d7268e471cb https://github.com/scylladb/scylladb/issues/11476 • CWE-908: Use of Uninitialized Resource •