CVE-2025-64343 is an authentication bypass vulnerability categorized under CWE-289 affecting the conda constructor tool, which is used to create installers for conda package collections. In versions 3.12.2 and earlier, the installation directory inherits permissions from its parent directory. When the parent directory is not restricted, permissions can be permissive enough to allow any authenticated local user to write to the installation directory. This means that during installation, any logged-in user can modify installation files, potentially injecting malicious code or altering the installation process. This vulnerability applies to both single-user and all-user installations. For single-user installations placed in shared directories, the permissive permissions remain after installation, extending the attack surface. The vulnerability does not require user interaction beyond being authenticated locally, and the attack vector is local, meaning an attacker must have some level of access to the system. The impact includes full compromise of confidentiality, integrity, and availability of the installed packages and potentially the host system if malicious code is executed. The issue was resolved in conda constructor version 3.13.0 by correcting the permission inheritance behavior to prevent unauthorized write access. There are no known exploits in the wild as of the publication date, but the high CVSS score of 7.8 reflects the significant risk posed by this vulnerability in multi-user environments.

For European organizations, this vulnerability poses a significant risk especially in environments where conda constructor is used to deploy software in shared or multi-user systems, such as research institutions, universities, and enterprises with collaborative development environments. Unauthorized modification of installation files can lead to the execution of malicious code, data breaches, or system compromise. The persistence of permissive permissions after installation in shared directories increases the risk of lateral movement and privilege escalation within networks. Confidentiality, integrity, and availability of critical software deployments can be severely impacted, potentially disrupting business operations or research activities. Organizations relying on conda for scientific computing or data analysis may face operational downtime or data integrity issues. The local nature of the attack vector means insider threats or compromised user accounts are primary concerns. Given the widespread use of conda in European academic and scientific communities, the impact could be broad if not mitigated promptly.

The primary mitigation is to upgrade conda constructor to version 3.13.0 or later, where the permission inheritance issue is fixed. Organizations should audit existing installations to verify directory permissions and restrict write access to installation directories to trusted administrators only. Avoid installing conda packages in shared directories accessible by multiple users unless strict access controls are enforced. Implement file system ACLs or POSIX permissions to limit write permissions to authorized users. Regularly monitor and audit file integrity in installation directories to detect unauthorized changes. Employ endpoint protection solutions that can detect anomalous modifications to software installations. Educate users about the risks of installing software in shared locations and enforce policies that restrict local user write access. For environments where upgrading is not immediately possible, consider isolating affected systems or using containerization to limit the impact of potential exploitation.