CVE-2020-11008

A flaw was found in git where credentials can be leaked through the use of a crafted URL. The crafted URL must contain a newline, empty host, or lack a scheme so that the credential helper is fulled into giving the information of a different host to the client. The highest threat from this vulnerability is to data confidentiality.

Mitigation

The most complete workaround is to disable credential helpers altogether:

git config --unset credential.helper  
git config --global --unset credential.helper  
git config --system --unset credential.helper  

An alternative is to avoid malicious URLs:

1. Examine the hostname and username portion of URLs fed to git clone or git fetch for the presence of encoded newlines (%0A) or syntactic oddities (e.g., <http:///host> with three slashes).
2. Avoid using submodules with untrusted repositories (don't use git clone --recurse-submodules; use git submodule update only after examining the URLs found in .gitmodules).
3. Avoid tools which may run git clone on untrusted URLs under the hood.
4. Avoid using the credential helper by only cloning publicly available repositories.