CVE-2025-32797

Conda-build Insecure Build Script Permissions Enabling Arbitrary Code Execution

Published Jun 16, 2025 CVSS 4.0 · 6 Medium EPSS < 1% KEV · Not listed

Description

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.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

conda

conda-build

affected

Version	Status	Constraints
`< 25.3.1`	affected	—

Configuration 1 [-]

cpe:2.3:a:anaconda:conda-build:*:*:*:*:*:*:*:*

No data.

No data available yet.

Remediation

No solution or workaround provided in the CVE record

Tracking

Advisories

Source	ID	Title
EUVD	EUVD-2025-18461	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.

Metrics

Attack Vector Local

Attack Complexity Low

Privileges Required None

Attack Requirements Present

User Interaction None

Vulnerable System Confidentiality Impact Low

Vulnerable System Integrity Impact High

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Local

Attack Complexity High

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.178% probability within 30 days)

Exploitation none

Automatable no

Technical Impact partial

References

Link	Providers
https://github.com/conda/conda-build/blob/3f06913bba22c4e1ef1065df9e00d86ac97f087c/conda_build/build.py#L3054-L3084
https://github.com/conda/conda-build/commit/d246e49c8f45e8033915156ee3d77769926f3c2e
https://github.com/conda/conda-build/pull/5
https://github.com/conda/conda-build/security/advisories/GHSA-vfp6-3v8g-vcmm

History

Aug 11, 2025 6:45 PM First appearance in the feed. Affected versions updated. Affected vendors updated. Scoring metrics updated View changes

Type	Values Removed	Values Added
First Time appeared		Anaconda Anaconda conda-build
CPEs		cpe:2.3:a:anaconda:conda-build::::::::
Vendors & Products		Anaconda Anaconda conda-build
Metrics		cvssV3_1 `{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}`

Jun 17, 2025 2:15 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Jun 16, 2025 8:15 PM Description updated View changes

Type	Values Removed	Values Added
Description	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.	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.

Jun 16, 2025 7:00 PM Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		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.
Title		Conda-build Insecure Build Script Permissions Enabling Arbitrary Code Execution
Weaknesses		CWE-277
References		https://github.com/conda/conda-build/blob/3f06913bba22c4e1ef1065df9e00d86ac97f087c/conda_build/build.py#L3054-L3084 https://github.com/conda/conda-build/commit/d246e49c8f45e8033915156ee3d77769926f3c2e https://github.com/conda/conda-build/pull/5 https://github.com/conda/conda-build/security/advisories/GHSA-vfp6-3v8g-vcmm
Metrics		cvssV4_0 `{'score': 6, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:H/SC:N/SI:N/SA:N'}`