CVE-2026-59654 Overview
CVE-2026-59654 is a resource management flaw in Apache CloudStack's scoped global configuration functionality. The vulnerability stems from a missing release of resources after their effective lifetime [CWE-772], affecting multiple modules and plugins of the CloudStack management server, including Quota and Host-HA. Over time, leaked resources accumulate and can degrade the management server, leading to a denial-of-service condition.
The issue affects Apache CloudStack versions 4.7.0 through 4.20.3.0 and 4.21.0.0 through 4.22.1.0. Fixed releases are available in versions 4.20.3.1 and 4.22.1.1.
Critical Impact
Sustained use of scoped global configuration operations can exhaust resources on the CloudStack management server, resulting in eventual denial of service for orchestrated cloud infrastructure.
Affected Products
- Apache CloudStack 4.7.0 through 4.20.3.0
- Apache CloudStack 4.21.0.0 through 4.22.1.0
- CloudStack management server modules including Quota and Host-HA
Discovery Timeline
- 2026-08-21 - CVE-2026-59654 published to NVD
- 2026-08-27 - Last updated in NVD database
Technical Details for CVE-2026-59654
Vulnerability Analysis
The defect exists in Apache CloudStack's scoped global configuration functionality. When configuration values are resolved and applied within scoped contexts, the underlying resources are not released after their effective lifetime ends. Each invocation retains references, connections, or in-memory objects that should have been reclaimed.
Several management server components consume this functionality, including the Quota plugin and Host-HA subsystem. Because these modules invoke the configuration lookup path repeatedly during normal operation, the leak accumulates without operator interaction. Over hours or days, resource consumption on the management server grows until performance degrades or services fail.
The result is an availability impact rather than confidentiality or integrity loss. Cloud operators may observe elevated memory usage, thread saturation, or unresponsive API endpoints on long-running management server instances.
Root Cause
The root cause is a missing release of a resource after effective lifetime [CWE-772]. Code paths that acquire per-scope configuration resources do not consistently invoke the corresponding release logic. Because scoped global configuration values are queried across many CloudStack subsystems, a single unreleased handle per operation produces a measurable leak at scale.
Attack Vector
The vulnerability requires network access to the CloudStack management API and authenticated privileges to trigger operations that exercise scoped global configuration. An authenticated user interacting with affected modules can accelerate resource consumption. In practice, the leak also progresses through routine management activity, so the impact can accumulate without deliberate abuse.
No verified proof-of-concept exploit is publicly available for CVE-2026-59654. The vulnerability manifests through normal invocation patterns rather than a discrete exploit payload. See the Apache Mailing List Discussion for maintainer notes.
Detection Methods for CVE-2026-59654
Indicators of Compromise
- Steadily increasing JVM heap usage or non-heap memory on the CloudStack management server without a corresponding workload increase.
- Growth in open file descriptors, database connections, or thread counts tied to the management server process.
- Management API latency increases or OutOfMemoryError entries in management-server.log on long-running instances.
Detection Strategies
- Inventory Apache CloudStack deployments and identify versions in the affected ranges (4.7.0–4.20.3.0 and 4.21.0.0–4.22.1.0).
- Baseline management server memory, thread, and connection metrics, then alert on sustained upward trends between restarts.
- Correlate resource growth with usage of Quota, Host-HA, and other modules that consume scoped global configuration.
Monitoring Recommendations
- Enable JVM metrics collection (heap, non-heap, GC activity, thread count) from the CloudStack management server and forward to a centralized analytics platform.
- Track uptime-adjusted resource utilization and alert on anomalies that persist across garbage collection cycles.
- Review management server logs for repeated exceptions or resource-allocation warnings originating from configuration lookup code paths.
How to Mitigate CVE-2026-59654
Immediate Actions Required
- Upgrade Apache CloudStack management servers to version 4.20.3.1 or 4.22.1.1 or later, which contain the fix.
- Schedule controlled restarts of unpatched management servers to reclaim leaked resources until the upgrade is applied.
- Restrict administrative API access to trusted networks and accounts to limit accelerated resource consumption.
Patch Information
Apache has released fixed versions 4.20.3.1 and 4.22.1.1. Refer to the Apache Mailing List Discussion for the official announcement and upgrade guidance. Operators running versions from 4.7.0 through 4.20.3.0 should move to the 4.20.3.1 branch. Operators on the 4.21.x or 4.22.x branch should move to 4.22.1.1 or later.
Workarounds
- No vendor-supplied workaround is documented; upgrading is the recommended remediation.
- As an interim measure, monitor management server resource usage and perform scheduled restarts before saturation occurs.
- Reduce non-essential automation that repeatedly queries scoped global configuration until the patched version is deployed.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
