CVE-2026-32588: Apache Cassandra DoS Vulnerability

CVE-2026-32588 Overview

CVE-2026-32588 is an authenticated Denial of Service (DoS) vulnerability affecting Apache Cassandra versions 4.0, 4.1, and 5.0. The vulnerability allows an authenticated user to degrade database performance by repeatedly changing passwords through the Cassandra Query Language (CQL) interface, resulting in elevated query latencies across the cluster.

Critical Impact

Authenticated attackers can exploit repeated password changes to cause resource exhaustion and significant query latency increases, effectively degrading database availability for legitimate users.

Affected Products

• Apache Cassandra 4.0 (prior to 4.0.20)
• Apache Cassandra 4.1 (prior to 4.1.11)
• Apache Cassandra 5.0 (prior to 5.0.7)

Discovery Timeline

• 2026-04-07 - CVE-2026-32588 published to NVD
• 2026-04-09 - Last updated in NVD database

Technical Details for CVE-2026-32588

Vulnerability Analysis

This vulnerability is classified as CWE-400 (Uncontrolled Resource Consumption), a resource exhaustion issue that allows authenticated users to negatively impact system availability. The attack requires network access and low-privilege authenticated credentials to execute. While no confidentiality or integrity impact exists, the availability impact is significant as it can degrade database performance across the entire Cassandra cluster.

The vulnerability exists within the password management functionality accessible through CQL. When a user repeatedly triggers password change operations, the system fails to properly rate-limit or throttle these requests, leading to excessive resource consumption that manifests as increased query latencies for all database operations.

Root Cause

The root cause stems from inadequate rate limiting on password change operations within the CQL authentication layer. Apache Cassandra's internal password hashing and credential management processes consume computational resources, and when invoked repeatedly in quick succession, these operations can monopolize system resources. The lack of throttling mechanisms allows an authenticated attacker to continuously trigger these resource-intensive operations, causing degradation in overall query performance.

Attack Vector

The attack is conducted over the network by an authenticated user with valid CQL credentials. The attacker establishes a connection to the Cassandra cluster and repeatedly issues password change commands through the CQL interface.

The exploitation sequence involves:

1. Authenticating to the Cassandra cluster using valid credentials
2. Issuing rapid, successive password change requests via CQL
3. The repeated hashing and credential update operations consume system resources
4. Query latencies increase across the cluster as resources become exhausted
5. Legitimate database operations experience degraded performance

For detailed technical information about this vulnerability, refer to the Apache Security Mailing List Post and the Openwall OSS Security Update.

Detection Methods for CVE-2026-32588

Indicators of Compromise

• Unusual spikes in ALTER ROLE or password change CQL commands from individual users
• Abnormally high CPU utilization on Cassandra nodes without corresponding increases in legitimate query volume
• Elevated query latencies across the cluster with no apparent infrastructure cause
• Authentication-related operations consuming disproportionate system resources

Detection Strategies

• Monitor CQL audit logs for excessive password change operations from single user accounts
• Implement alerting on sudden increases in average query latency without corresponding traffic increases
• Track per-user authentication operation frequency and alert on anomalous patterns
• Deploy application-level monitoring to detect resource exhaustion patterns

Monitoring Recommendations

• Enable Cassandra audit logging to capture all authentication-related CQL commands
• Configure metrics collection for query latency percentiles (p95, p99) with baseline alerting
• Monitor system resource utilization (CPU, memory) correlated with authentication events
• Implement centralized log aggregation to identify patterns across cluster nodes

How to Mitigate CVE-2026-32588

Immediate Actions Required

• Upgrade Apache Cassandra to patched versions: 4.0.20, 4.1.11, or 5.0.7
• Review user accounts and revoke credentials for any accounts not actively required
• Implement network-level access controls to limit CQL access to trusted sources
• Enable audit logging to track password change operations for incident response

Patch Information

Apache has released security patches addressing this vulnerability. Users are recommended to upgrade to the following fixed versions:

For upgrade instructions and release notes, consult the Apache Security Mailing List Post.

Workarounds

• Implement application-level rate limiting on password change operations if patching is not immediately possible
• Restrict CQL network access using firewall rules to trusted IP addresses only
• Review and minimize the number of user accounts with password change capabilities
• Monitor for exploitation attempts while planning the upgrade path

# Example: Restrict CQL port access to trusted networks using iptables
iptables -A INPUT -p tcp --dport 9042 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 9042 -j DROP