CVE-2023-5752 is a medium severity command injection vulnerability affecting pip, the Python package installer, specifically versions prior to 23.3. The vulnerability arises when pip installs a package from a Mercurial (hg) version control system URL using the syntax 'pip install hg+...'. In this process, the Mercurial revision parameter can be manipulated to inject arbitrary configuration options into the underlying 'hg clone' command via the '--config' flag. This improper neutralization of special elements (CWE-77) allows an attacker to control Mercurial's configuration during the clone operation, potentially redirecting the repository source or altering repository behavior. The vulnerability requires the attacker to have the ability to specify the Mercurial revision parameter, which typically implies some level of control over the package installation command or the package source specification. The CVSS 3.1 score of 5.5 reflects that the attack vector is local (AV:L), requires low privileges (PR:L), no user interaction (UI:N), and impacts integrity (I:H) but not confidentiality or availability. There are no known exploits in the wild at the time of publication. This vulnerability does not affect users who do not install packages from Mercurial repositories, limiting its scope. The root cause is insufficient sanitization of the revision parameter, allowing command injection into the Mercurial clone process. The vulnerability was publicly disclosed on October 24, 2023, by the Python Software Foundation (PSF).

For European organizations, the primary impact of CVE-2023-5752 lies in the potential integrity compromise of software supply chains that rely on pip installations from Mercurial repositories. An attacker exploiting this vulnerability could manipulate the source code or configuration of installed packages by injecting malicious repository configurations, leading to the installation of tampered or malicious code. This can result in compromised applications, backdoors, or further lateral movement within the network. While the vulnerability does not directly affect confidentiality or availability, the integrity breach can have cascading effects, including data breaches or system compromise. Organizations with automated build systems, continuous integration pipelines, or development environments that use Mercurial-based package sources are at higher risk. Since Mercurial is less commonly used than Git, the affected population is smaller but still significant in sectors where Mercurial remains in use. The medium severity rating indicates a moderate risk, but the potential for supply chain attacks elevates the importance of timely remediation. European entities involved in software development, especially those in regulated industries or critical infrastructure, must consider this vulnerability seriously to maintain software integrity and trust.

1. Upgrade pip to version 23.3 or later immediately, as this version contains the fix for CVE-2023-5752. 2. Avoid installing Python packages from Mercurial VCS URLs unless absolutely necessary; prefer more secure and widely used sources like PyPI or Git repositories. 3. Audit and sanitize all inputs related to package installation commands, especially those involving Mercurial revisions, to prevent injection of malicious configuration options. 4. Implement strict controls and monitoring on build and deployment pipelines to detect unusual or unauthorized package sources or configurations. 5. Use virtual environments and containerization to isolate package installations and limit the impact of potential compromises. 6. Educate developers and DevOps teams about the risks of using Mercurial URLs in pip installations and encourage best practices for secure package management. 7. Employ software composition analysis tools to detect and alert on vulnerable pip versions or unsafe package sources. 8. Review and restrict permissions for users who can execute pip install commands with Mercurial URLs to reduce the attack surface.