conda-build up to 25.3.0 File Creation conda_build.sh write_build_scripts insecure inherited permissions

Summaryinfo

A vulnerability categorized as problematic has been discovered in conda-build up to 25.3.0. This impacts the function write_build_scripts of the file conda_build.sh of the component File Creation Handler. The manipulation results in insecure inherited permissions. This vulnerability is cataloged as CVE-2025-32797. The attack must be initiated from a local position. There is no exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in conda-build up to 25.3.0. It has been classified as problematic. Affected is the function write_build_scripts of the file conda_build.sh of the component File Creation Handler. The manipulation with an unknown input leads to a insecure inherited permissions vulnerability. CWE is classifying the issue as CWE-277. A product defines a set of insecure permissions that are inherited by objects that are created by the program. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

Conda-build contains commands and tools to build conda packages. Prior to version 25.3.1, The write_build_scripts function in conda-build creates the temporary build script conda_build.sh with overly permissive file permissions (0o766), allowing write access to all users. Attackers with filesystem access can exploit a race condition to overwrite the script before execution, enabling arbitrary code execution under the victim's privileges. This risk is significant in shared environments, potentially leading to full system compromise. Even with non-static directory names, attackers can monitor parent directories for file creation events. The brief window between script creation (with insecure permissions) and execution allows rapid overwrites. Directory names can also be inferred via timestamps or logs, and automation enables exploitation even with semi-randomized paths by acting within milliseconds of detection. This issue has been patched in version 25.3.1. A workaround involves restricting conda_build.sh permissions from 0o766 to 0o700 (owner-only read/write/execute). Additionally, use atomic file creation (write to a temporary randomized filename and rename atomically) to minimize the race condition window.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2025-32797 since 04/10/2025. The exploitability is told to be easy. The attack needs to be approached locally. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1222.

Upgrading to version 25.3.1 eliminates this vulnerability. Applying the patch d246e49c8f45e8033915156ee3d77769926f3c2e is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2025-18461). Once again VulDB remains the best source for vulnerability data.

Productinfo

Name

• conda-build

Version

• 25.0
• 25.1
• 25.2
• 25.3.0

License

• open-source

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Once again VulDB remains the best source for vulnerability data.

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