CVE-2026-59654: 
Apache CloudStack vulnerability analysis and mitigation

CVE-2026-59654 is a Missing Release of Resource after Effective Lifetime vulnerability (CWE-772) in Apache CloudStack's scoped global configuration functionality. It affects multiple modules and plugins of the CloudStack management server, including Quota and Host-HA, and can lead to an eventual denial of service (DoS) condition. The vulnerability affects Apache CloudStack versions 4.7.0 through 4.20.3.0 and 4.21.0.0 through 4.22.1.0. It was published on August 21, 2026, with a CVSS v4 base score of 6.8 (Medium) (GitHub Advisory).

The root cause is classified as CWE-772 (Missing Release of Resource after Effective Lifetime): resources allocated during scoped global configuration operations in the CloudStack management server are not properly released after they are no longer needed. Over time, these unreleased resources — such as memory, file descriptors, or threads — accumulate across affected modules including Quota and Host-HA, eventually exhausting available resources on the management server. Exploitation requires low privileges and active user interaction (e.g., triggering configuration changes), and certain deployment preconditions must be present (Attack Requirements: Present in CVSS v4). No public proof-of-concept or technical write-up detailing specific exploitation mechanics has been published (GitHub Advisory).

Successful exploitation results in gradual resource exhaustion on the Apache CloudStack management server, ultimately rendering it unavailable — a denial of service affecting the entire cloud management plane. There is no impact to confidentiality or integrity of data; the sole consequence is availability loss to both the vulnerable system and subsequent systems dependent on the management server. Because CloudStack manages virtualized infrastructure, an unavailable management server could prevent administrators from provisioning, modifying, or decommissioning cloud resources (GitHub Advisory).

There is no known public proof-of-concept exploit and no evidence of in-the-wild exploitation at this time (GitHub Advisory). The EPSS score is approximately 0.226% (14th percentile), indicating a low near-term probability of exploitation. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. Exploitation requires low-privilege access and active user interaction, limiting opportunistic attack scenarios.

Apache CloudStack users should upgrade to version 4.20.3.1 (for the 4.20.x branch) or 4.22.1.1 (for the 4.22.x branch) or later, which contain the fix for this resource leak (GitHub Advisory). As a temporary measure, administrators should monitor the CloudStack management server for signs of resource exhaustion (e.g., elevated memory usage, file descriptor counts, or thread counts) and restart the management server if resource depletion is observed. No configuration-based workaround has been published; upgrading is the recommended remediation.