[Security-announce][CVE-2023-5752] Mercurial configuration injectable in repo revision when installing via pip

When installing a package from a Mercurial VCS URL (ie "pip install hg+...") with pip prior to v23.3, the specified Mercurial revision could be used to inject arbitrary configuration options to the "hg clone" call (ie "--config"). Controlling the Mercurial configuration can modify how and which repository is installed.

This vulnerability does not affect users who aren't installing Mercurial VCS URLs.

This is a *MEDIUM* severity vulnerability.

*Affected versions:*

pip before v23.3 are affected by this vulnerability.

*Remediation:*

• Upgrade to at least pip v23.3
• Don't clone Mercurial repositories or allow uncontrolled input to the target Mercurial URL and revision.

*References:*

• https://www.cve.org/CVERecord?id=CVE-2023-5752
• https://github.com/pypa/pip/pull/12306