PatchSiren cyber security CVE debrief
CVE-2026-0864 Python Software Foundation CVE debrief
CVE-2026-0864 is a vulnerability in the Python configparser module that occurs when writing configuration files with multi-line text values containing carriage return characters. An attacker controlling the written value can inject unexpected keys and values into the resulting file. The vulnerability has a CVSS score of 4.1 and is classified as medium severity. The CVE was published on June 23, 2026, and last modified on June 25, 2026. The vulnerability affects the Python project, which is the vendor. There are multiple references available, including commits and discussions on the Python GitHub repository.
- Vendor
- Python Software Foundation
- Product
- CPython
- CVSS
- MEDIUM 4.1
- CISA KEV
- Not listed in stored evidence
- Original CVE published
- 2026-06-23
- Original CVE updated
- 2026-06-25
- Advisory published
- 2026-06-23
- Advisory updated
- 2026-06-25
Who should care
Developers and users of the Python programming language should be aware of this vulnerability, as it can be exploited to inject malicious configuration into files. This could potentially lead to security issues if the configuration is used to control sensitive operations or data access. The vulnerability is particularly relevant for applications that use the configparser module to generate configuration files based on user input.
Technical summary
The vulnerability arises from the configparser module's handling of multi-line text values with carriage return characters. When writing configuration files, the module does not properly sanitize the input, allowing an attacker to inject arbitrary keys and values. This can be exploited by controlling the written value, potentially leading to configuration tampering. The vulnerability has been addressed through multiple commits in the Python GitHub repository, including 0adb386, 5858e42, 71f2e02, and aaf850f.
Defensive priority
This vulnerability requires a medium priority defensive response. Affected applications should review their use of the configparser module and ensure that user input is properly sanitized before writing configuration files. Developers should consider applying patches or updating to a version of Python that addresses this vulnerability.
Recommended defensive actions
- Review and sanitize user input to the configparser module
- Apply patches or update to a fixed version of Python
- Monitor configuration files for unexpected changes
- Implement additional validation and error handling for configuration data
- Consider using alternative configuration parsing libraries
Evidence notes
The CVE record and NVD detail provide official information about the vulnerability. Multiple commits and discussions on the Python GitHub repository offer additional context and fixes for the issue. The vulnerability appears to be addressed through various commits, including 0adb386, 5858e42, 71f2e02, and aaf850f.
Official resources
This article is AI-assisted and based on the supplied source corpus.