CVE-2026-86471 in CouchDB
Summary
by MITRE • 10/20/2026
An unvalidated runtime configuration value in Apache CouchDB 3.5.2 and below on all platforms allows a CouchDB server admin to run arbitrary shell commands as the CouchDB operating system user.
Users are recommended to upgrade to version 3.5.3, which fixes this issue.
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Analysis
by VulDB Data Team • 10/20/2026
The vulnerability identified in Apache CouchDB versions 3.5.2 and earlier represents a critical security flaw rooted in improper input validation of runtime configuration parameters. This specific weakness allows an authenticated administrator with access to the server's configuration interface or environment variables to inject arbitrary shell commands that are executed by the underlying operating system under the context of the CouchDB service account. The core technical failure lies in the application's handling of certain configuration values, which are passed directly to system-level command interpreters without sufficient sanitization or validation checks. This lack of rigorous input filtering creates a direct pathway for code injection, bypassing standard access controls that would otherwise restrict administrative actions to safe operations within the database engine itself.
From an operational perspective, this vulnerability poses severe risks to data integrity and confidentiality. Because the executed commands run with the privileges of the CouchDB user, attackers can potentially read sensitive configuration files, modify database storage locations, or exfiltrate stored documents if file system permissions allow such access. In more complex deployments where the service account has elevated privileges or is part of a privileged group, the impact escalates to full server compromise. An attacker could install backdoors, pivot into other network segments, or disrupt availability by terminating critical processes. The ability to execute arbitrary commands effectively neutralizes the security boundary between the application layer and the operating system, turning an administrative tool intended for legitimate configuration management into a vector for complete system takeover.
This flaw aligns with CWE-78 Improper Neutralization of Special Elements used in an OS Command, commonly known as OS Command Injection. The attack scenario is further characterized by its alignment with MITRE ATT&CK techniques related to command and script interpretation, specifically those involving local execution through configuration manipulation or service account abuse. Unlike remote code execution vulnerabilities that exploit network-facing services directly, this vulnerability requires initial authenticated access, typically via the CouchDB admin interface or environment variable injection during containerized deployments where environment variables are often used for runtime configuration. This distinction highlights the importance of securing administrative endpoints and restricting who can modify deployment configurations in production environments.
To mitigate this risk, organizations running Apache CouchDB must immediately upgrade to version 3.5.3 or later, which includes patches that enforce strict validation on all runtime configuration values before they are processed by system commands. In addition to upgrading, administrators should adhere to the principle of least privilege by ensuring the CouchDB operating system user has minimal permissions necessary for database operation, thereby limiting the potential impact if a vulnerability is exploited in other components. Furthermore, access to administrative interfaces and environment variable configurations should be tightly controlled using strong authentication mechanisms and network segmentation. Regular auditing of configuration changes and monitoring for unusual process execution patterns can also aid in detecting attempts to exploit this class of vulnerabilities before significant damage occurs.