diff --git a/.github/workflows/issue-416-security-round4.yml b/.github/workflows/issue-416-security-round4.yml
new file mode 100644
index 000000000..71f514ae3
--- /dev/null
+++ b/.github/workflows/issue-416-security-round4.yml
@@ -0,0 +1,136 @@
+name: Issue 416 Security Round 4
+
+on:
+  push:
+    branches:
+      - feat/issue-416-backup-destinations
+    paths:
+      - .github/workflows/issue-416-security-round4.yml
+
+permissions:
+  contents: write
+
+jobs:
+  fix-and-verify:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v5
+        with:
+          ref: feat/issue-416-backup-destinations
+      - uses: pnpm/action-setup@v5
+        with:
+          version: 10.22.0
+      - uses: actions/setup-node@v5
+        with:
+          node-version: 24.4.0
+          cache: pnpm
+      - run: pnpm install --frozen-lockfile
+      - name: Apply guarded final hardening
+        run: |
+          python - <<'PY'
+          from pathlib import Path
+
+          def replace_once(text, old, new, label):
+              count = text.count(old)
+              if count != 1:
+                  raise SystemExit(f"{label}: expected one match, found {count}")
+              return text.replace(old, new, 1)
+
+          # Force certificate verification on for FTP even if the execution
+          # environment sets insecure rclone defaults. CLI options override env.
+          utils = Path("packages/server/src/utils/backups/utils.ts")
+          text = utils.read_text()
+          old = '''\t\tif (destination.secretAccessKey) {\n\t\t\tconst obscuredPassword = await obscureRclonePassword(\n\t\t\t\tdestination.secretAccessKey,\n\t\t\t);\n\t\t\tflags.push(`--${backend}-pass=${quote([obscuredPassword])}`);\n\t\t}\n\t\tflags.push(...additionalFlags);\n\t\treturn {\n'''
+          new = '''\t\tif (destination.secretAccessKey) {\n\t\t\tconst obscuredPassword = await obscureRclonePassword(\n\t\t\t\tdestination.secretAccessKey,\n\t\t\t);\n\t\t\tflags.push(`--${backend}-pass=${quote([obscuredPassword])}`);\n\t\t}\n\t\tflags.push(...additionalFlags);\n\t\tif (provider === RCLONE_DESTINATION_PROVIDERS.FTP) {\n\t\t\t// Command-line flags override RCLONE_* environment defaults. Keep\n\t\t\t// certificate verification enabled even on a misconfigured runner.\n\t\t\tflags.push(\n\t\t\t\t"--ftp-no-check-certificate=false",\n\t\t\t\t"--no-check-certificate=false",\n\t\t\t);\n\t\t}\n\t\treturn {\n'''
+          text = replace_once(text, old, new, "FTP secure CLI overrides")
+          utils.write_text(text)
+
+          # Redact a complete POSIX shell word, including concatenated quoted
+          # and escaped chunks emitted by shell-quote for embedded quotes/spaces.
+          redact = Path("packages/server/src/utils/backups/redact.ts")
+          text = redact.read_text()
+          old_regex = r'''\t\t/(--(?:s3-access-key-id|s3-secret-access-key|ftp-pass|sftp-pass|sftp-key-file-pass)=)(?:\"(?:[^\"\\\\]|\\\\.)*\"|'(?:[^'\\\\]|\\\\.)*'|[^\\s]+)/g,'''
+          new_regex = r'''\t\t/(--(?:s3-access-key-id|s3-secret-access-key|ftp-pass|sftp-pass|sftp-key-file-pass)=)(?:(?:\"(?:[^\"\\\\]|\\\\.)*\"|'(?:[^'\\\\]|\\\\.)*'|\\\\[^\\r\\n]|[^\\s\"'\\\\])+)/g,'''
+          if old_regex not in text:
+              raise SystemExit("redaction regex anchor not found")
+          text = text.replace(old_regex, new_regex, 1)
+          redact.write_text(text)
+
+          # Real shell-quote adversarial regression coverage.
+          test = Path("apps/dokploy/__test__/backups/redact-credentials.test.ts")
+          text = test.read_text()
+          if 'from "shell-quote"' not in text:
+              text = text.replace(
+                  'import { describe, expect, it } from "vitest";',
+                  'import { quote } from "shell-quote";\nimport { describe, expect, it } from "vitest";',
+                  1,
+              )
+          extra = '''\n\tit("should fully redact shell-quote output with embedded quotes and whitespace", () => {\n\t\tconst secret = `PART_A' PART_B\\" $PART_C;\\\\PART_D`;\n\t\tconst cmd = `rclone lsf --s3-secret-access-key=${quote([secret])} --s3-region=us-east-1 :s3:bucket`;\n\t\tconst redacted = redactRcloneCredentials(cmd);\n\n\t\tfor (const fragment of ["PART_A", "PART_B", "PART_C", "PART_D"]) {\n\t\t\texpect(redacted).not.toContain(fragment);\n\t\t}\n\t\texpect(redacted).toContain('--s3-secret-access-key="[REDACTED]"');\n\t\texpect(redacted).toContain("--s3-region=us-east-1");\n\t});\n'''
+          idx = text.rfind("\n});")
+          if idx == -1:
+              raise SystemExit("redaction describe end not found")
+          if "fully redact shell-quote output" not in text:
+              text = text[:idx] + extra + text[idx:]
+          test.write_text(text)
+
+          # Verify secure CLI override generation at runtime.
+          backup_test = Path("apps/dokploy/__test__/utils/backups.test.ts")
+          text = backup_test.read_text()
+          extra = '''\n\ttest("forces certificate verification on after user flags", async () => {\n\t\tconst result = await getRclonePathAndFlags(\n\t\t\tdestination({\n\t\t\t\tprovider: RCLONE_DESTINATION_PROVIDERS.FTP,\n\t\t\t\tendpoint: "storage.example.com",\n\t\t\t\taccessKey: "backup-user",\n\t\t\t\tsecretAccessKey: "",\n\t\t\t\tregion: "",\n\t\t\t\tbucket: "backups",\n\t\t\t\tadditionalFlags: ["--ftp-explicit-tls"],\n\t\t\t}),\n\t\t);\n\t\texpect(result.flags.slice(-2)).toEqual([\n\t\t\t"--ftp-no-check-certificate=false",\n\t\t\t"--no-check-certificate=false",\n\t\t]);\n\t});\n'''
+          idx = text.rfind("\n});")
+          if idx == -1:
+              raise SystemExit("FTP TLS describe end not found")
+          if "forces certificate verification on after user flags" not in text:
+              text = text[:idx] + extra + text[idx:]
+          backup_test.write_text(text)
+          PY
+      - name: Format changed files
+        run: |
+          pnpm exec biome check --write \
+            packages/server/src/utils/backups/utils.ts \
+            packages/server/src/utils/backups/redact.ts \
+            apps/dokploy/__test__/backups/redact-credentials.test.ts \
+            apps/dokploy/__test__/utils/backups.test.ts
+      - name: Focused backup and security regressions
+        run: |
+          pnpm --filter=dokploy exec vitest --config __test__/vitest.config.ts \
+            __test__/backups/redact-credentials.test.ts \
+            __test__/utils/backups.test.ts \
+            __test__/utils/issue-416-path-safety.test.ts --run
+      - name: Typecheck
+        run: pnpm typecheck
+      - name: Server build
+        run: pnpm server:build
+      - name: Biome clean
+        run: |
+          pnpm exec biome check \
+            packages/server/src/utils/backups/utils.ts \
+            packages/server/src/utils/backups/redact.ts \
+            apps/dokploy/__test__/backups/redact-credentials.test.ts \
+            apps/dokploy/__test__/utils/backups.test.ts
+      - name: Verify final security invariants
+        run: |
+          python - <<'PY'
+          from pathlib import Path
+          u=Path("packages/server/src/utils/backups/utils.ts").read_text()
+          assert '"--ftp-no-check-certificate=false"' in u
+          assert '"--no-check-certificate=false"' in u
+          r=Path("packages/server/src/utils/backups/redact.ts").read_text()
+          assert "\\\\[^\\r\\n]" in r
+          t=Path("apps/dokploy/__test__/backups/redact-credentials.test.ts").read_text()
+          assert 'fully redact shell-quote output' in t
+          print("environment-default and shell-word redaction invariants verified")
+          PY
+      - name: Commit verified hardening
+        run: |
+          git config user.name "github-actions[bot]"
+          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
+          git add \
+            packages/server/src/utils/backups/utils.ts \
+            packages/server/src/utils/backups/redact.ts \
+            apps/dokploy/__test__/backups/redact-credentials.test.ts \
+            apps/dokploy/__test__/utils/backups.test.ts
+          if ! git diff --cached --quiet; then
+            git commit -m "fix: harden rclone environment and credential redaction"
+            git push origin HEAD:feat/issue-416-backup-destinations
+          fi