CVE-2025-26511: Instaclustr Cassandra-Lucene-Index allows bypass of Cassandra RBAC

Summary / Details Systems running the Instaclustr fork of Stratio’s Cassandra-Lucene-Index plugin versions 4.0-rc1-1.0.0 through 4.0.16-1.0.0 and 4.1.0-1.0.0 through 4.1.8-1.0.0, installed into Apache Cassandra version 4.x, are susceptible to a vulnerability which when successfully exploited could allow authenticated Cassandra users to remotely bypass RBAC to access data and and escalate their privileges.

Affected Versions

• Cassandra-Lucene-Index plugin versions 4.0-rc1-1.0.0 through 4.0.16-1.0.0
• versions 4.1.0-1.0.0 through 4.1.8-1.0.0 when installed into Apache Cassandra version 4.x.

Required Configuration for Exploit These are the conditions required to enable exploit:

1. Cassandra 4.x
2. Vulnerable version of the Cassandra-Lucene-Index plugin configured for use
3. Data added to tables
4. Lucene index created
5. Cassandra flush has run

Mitigation/Prevention Mitigation requires dropping all Lucene indexes and stopping use of the plugin. Exploit will be possible any time the required conditions are met.

Solution Upgrade to a fixed version of the Cassandra-Lucene-Index plugin. Review users in Cassandra to validate all superuser privileges.