Improper Input Validation Affecting git package, versions <2.24.1-r0

Note: Versions mentioned in the description apply only to the upstream git package and not the git package as distributed by Alpine. See How to fix? for Alpine:3.16 relevant fixed versions and status.

Arbitrary command execution is possible in Git before 2.20.2, 2.21.x before 2.21.1, 2.22.x before 2.22.2, 2.23.x before 2.23.1, and 2.24.x before 2.24.1 because a "git submodule update" operation can run commands found in the .gitmodules file of a malicious repository.

• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-19604
• https://public-inbox.org/git/xmqqr21cqcn9.fsf@gitster-ct.c.googlers.com/
• https://raw.githubusercontent.com/git/git/master/Documentation/RelNotes/2.24.1.txt
• https://www.debian.org/security/2019/dsa-4581
• https://security-tracker.debian.org/tracker/CVE-2019-19604
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/HCYSSCA5ZTEP46SB4XRPSQGFV2L3NKMZ/
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/N6UGTEOXWIYSM5KDZL74QD2GK6YQNQCP/
• https://security.gentoo.org/glsa/202003-30
• https://gitlab.com/gitlab-com/gl-security/disclosures/blob/master/003_git_submodule/advisory.md
• http://www.openwall.com/lists/oss-security/2019/12/13/1
• http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00056.html
• http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00003.html
• http://people.ubuntu.com/~ubuntu-security/cve/CVE-2019-19604
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HCYSSCA5ZTEP46SB4XRPSQGFV2L3NKMZ/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/N6UGTEOXWIYSM5KDZL74QD2GK6YQNQCP/
• https://public-inbox.org/git/xmqqr21cqcn9.fsf%40gitster-ct.c.googlers.com/