CVE-2026-42301
Description
A flaw was found in pyp2spec, a tool that generates Fedora RPM spec files for Python projects. This vulnerability allows a malicious Python Package Index (PyPI) package to execute arbitrary commands on a build machine. This occurs because pyp2spec writes PyPI package metadata, such as the summary field, into the generated spec file without properly escaping RPM macro directives. When a packager subsequently runs rpmbuild, these unescaped directives are evaluated, leading to the execution of arbitrary commands.
Statement
Red Hat Product Security has determined that this vulnerability does not affect any currently supported Red Hat product. This assessment may evolve based on further analysis and discovery. For more information about this vulnerability and the products it affects, please see the linked references.
Mitigation
To mitigate this issue, Red Hat recommends that packagers meticulously review spec files generated by `pyp2spec` before executing `rpmbuild`, particularly when the source PyPI package originates from untrusted or unverified sources. Furthermore, performing RPM builds within isolated and sandboxed environments can effectively limit the potential impact of arbitrary command execution.
Understanding the Weakness (CWE)
Confidentiality,Integrity,Availability,Non-Repudiation
Technical Impact: Execute Unauthorized Code or Commands; DoS: Crash, Exit, or Restart; Read Files or Directories; Modify Files or Directories; Read Application Data; Modify Application Data; Hide Activities
Attackers could execute unauthorized operating system commands, which could then be used to disable the product, or read and modify data for which the attacker does not have permissions to access directly. Since the targeted application is directly executing the commands instead of the attacker, any malicious activities may appear to come from the application or the application's owner.
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
