CVE-2025-32797 is a medium-severity vulnerability affecting conda-build versions prior to 25.3.1. Conda-build is a tool used to create conda packages, commonly employed in software development and data science environments. The vulnerability arises from the write_build_scripts function, which creates a temporary build script named conda_build.sh with overly permissive file permissions set to 0o766. This permission setting allows any user on the system to write to the script file. Because the script is created and then executed shortly thereafter, an attacker with filesystem access can exploit a race condition by overwriting the script during the brief window between its creation and execution. This enables arbitrary code execution with the privileges of the user running conda-build. The risk is particularly significant in shared or multi-user environments, such as shared servers or CI/CD pipelines, where multiple users have filesystem access. Even when directory names are randomized or non-static, attackers can monitor parent directories for file creation events and rapidly overwrite the script using automated tools, exploiting the race condition within milliseconds. The vulnerability is classified under CWE-277 (Insecure Inherited Permissions), indicating improper permission settings that allow unauthorized modification. The issue has been addressed in conda-build version 25.3.1 by correcting the file permissions and recommending atomic file creation techniques (writing to a temporary randomized filename and then renaming atomically) to minimize the race window. A practical workaround prior to patching involves manually restricting the permissions of conda_build.sh to 0o700, limiting read/write/execute access to the owner only, thereby preventing unauthorized overwrites.

For European organizations, especially those utilizing conda-build in shared development environments, research institutions, or cloud-based CI/CD pipelines, this vulnerability poses a significant risk. Exploitation can lead to arbitrary code execution under the victim's privileges, potentially resulting in unauthorized access, data manipulation, or lateral movement within the network. In environments where conda-build runs with elevated privileges or on critical infrastructure, the impact could escalate to full system compromise. The vulnerability's exploitation does not require user interaction or authentication, increasing its threat level in multi-user systems. Given the widespread use of conda in scientific computing, machine learning, and software development across Europe, organizations in academia, technology sectors, and cloud service providers are particularly at risk. The ability to exploit the race condition rapidly means attackers can automate attacks, increasing the likelihood of successful compromise in shared environments. This could lead to data breaches, disruption of development workflows, and potential damage to intellectual property or critical research data.

1. Upgrade conda-build to version 25.3.1 or later immediately to apply the official patch that corrects file permissions and implements atomic file creation. 2. Until patching is possible, manually change the permissions of the conda_build.sh script to 0o700 immediately after creation to restrict access to the owner only, preventing unauthorized overwrites. 3. Implement filesystem monitoring to detect rapid file modifications or creations in build directories, enabling early detection of potential exploitation attempts. 4. Restrict filesystem access on shared systems by enforcing strict user isolation and limiting write permissions to build directories only to trusted users. 5. Where feasible, run conda-build processes within isolated containers or virtual machines to contain potential exploitation impact. 6. Review and harden CI/CD pipeline configurations to ensure build scripts are not exposed to unauthorized users and that build environments are ephemeral and isolated. 7. Educate developers and system administrators about the risks of race conditions and insecure file permissions in build tools to promote proactive security practices.