Disable git v2 protocol temporarily

GITALY_SERVER_VERSION

-1.14.0
+1.14.1
\ No newline at end of file

changelogs/unreleased/security-2780-disable-git-v2-protocol.yml

+---
+title: Disable git v2 protocol temporarily
+merge_request:
+author:
+type: security

doc/administration/git_protocol.md

@@ -5,6 +5,13 @@ description: "Set and configure Git protocol v2"
 # Configuring Git Protocol v2
 
 > [Introduced](https://gitlab.com/gitlab-org/gitlab-ce/issues/46555) in GitLab 11.4.
+> [Temporarily disabled](https://gitlab.com/gitlab-org/gitlab-ce/issues/55769) in GitLab 11.5.8, 11.6.6, 11.7.1, and 11.8+
+
+NOTE: **Note:**
+Git protocol v2 support has been [temporarily disabled](https://gitlab.com/gitlab-org/gitlab-ce/issues/55769),
+as a feature used to hide certain internal references does not function when it
+is enabled, and this has a security impact. Once this problem has been resolved,
+protocol v2 support will be re-enabled.
 
 Git protocol v2 improves the v1 wire protocol in several ways and is
 enabled by default in GitLab for HTTP requests. In order to enable SSH,