diff --git a/.gitea/workflows/runtime-distribution.yml b/.gitea/workflows/runtime-distribution.yml
index 7c9ac78..3e14fe6 100644
--- a/.gitea/workflows/runtime-distribution.yml
+++ b/.gitea/workflows/runtime-distribution.yml
@@ -320,10 +320,12 @@ jobs:
         working-directory: govoplan
         env:
           VERSION: ${{ inputs.version }}
+          SOURCE_COMMIT: ${{ gitea.sha }}
           GITEA_RELEASE_TOKEN: ${{ secrets.GOVOPLAN_RELEASE_TOKEN }}
         run: |
           python tools/release/publish-runtime-release.py \
             --tag "v$VERSION" \
+            --target-commit "$SOURCE_COMMIT" \
             --title "GovOPlaN v$VERSION runtime distribution" \
             --asset runtime-output/govoplan-deploy.pyz \
             --asset runtime-output/govoplan-deploy.pyz.sig \
diff --git a/tests/test_runtime_distribution_build.py b/tests/test_runtime_distribution_build.py
index 8003d66..083f264 100644
--- a/tests/test_runtime_distribution_build.py
+++ b/tests/test_runtime_distribution_build.py
@@ -9,6 +9,8 @@ import shutil
 import sys
 import tempfile
 import unittest
+from unittest.mock import patch
+from urllib.error import HTTPError
 
 
 ROOT = Path(__file__).resolve().parents[1]
@@ -32,6 +34,10 @@ DEPLOYER_BUILD = _load(
     "build_deployer_zipapp",
     ROOT / "tools/deployment/build-deployer-zipapp.py",
 )
+PUBLISH = _load(
+    "publish_runtime_release",
+    ROOT / "tools/release/publish-runtime-release.py",
+)
 
 
 class RuntimeDistributionBuildTests(unittest.TestCase):
@@ -99,6 +105,20 @@ class RuntimeDistributionBuildTests(unittest.TestCase):
             dockerfile,
         )
 
+    def test_web_runtime_uses_only_writable_tmpfs_for_nginx_temp_files(self) -> None:
+        nginx = (ROOT / "tools/release/runtime/nginx.conf").read_text(
+            encoding="utf-8"
+        )
+
+        for temporary_path in (
+            "client_body_temp_path /tmp/client_temp;",
+            "fastcgi_temp_path /tmp/fastcgi_temp;",
+            "proxy_temp_path /tmp/proxy_temp;",
+            "scgi_temp_path /tmp/scgi_temp;",
+            "uwsgi_temp_path /tmp/uwsgi_temp;",
+        ):
+            self.assertIn(temporary_path, nginx)
+
     def test_workflow_verifies_portable_bootstrap_artifacts_before_execution(
         self,
     ) -> None:
@@ -128,6 +148,79 @@ class RuntimeDistributionBuildTests(unittest.TestCase):
         self.assertIn("runtime-smoke-amd64.json", workflow)
         self.assertIn("runtime-smoke-arm64.json", workflow)
 
+    def test_workflow_binds_the_release_tag_to_the_workflow_commit(self) -> None:
+        workflow = (ROOT / ".gitea/workflows/runtime-distribution.yml").read_text(
+            encoding="utf-8"
+        )
+        publisher = (ROOT / "tools/release/publish-runtime-release.py").read_text(
+            encoding="utf-8"
+        )
+
+        self.assertIn("SOURCE_COMMIT: ${{ gitea.sha }}", workflow)
+        self.assertIn('--target-commit "$SOURCE_COMMIT"', workflow)
+        self.assertIn('"target_commitish": target_commit', publisher)
+        self.assertIn("self._resolve_commit(tag) != target_commit", publisher)
+
+    def test_runtime_publisher_rejects_a_tag_on_another_commit(self) -> None:
+        publisher = PUBLISH.GiteaReleasePublisher(
+            base_url="https://git.example.test",
+            owner="GovOPlaN",
+            repo="govoplan",
+            token="secret",
+        )
+        target = "1" * 40
+        with (
+            patch.object(
+                publisher,
+                "_resolve_commit",
+                side_effect=(target, "2" * 40),
+            ),
+            self.assertRaisesRegex(PUBLISH.PublishError, "another commit"),
+        ):
+            publisher.release(
+                tag="v1.2.3",
+                target_commit=target,
+                title="Release",
+                body="Body",
+            )
+
+    def test_runtime_publisher_creates_the_tag_at_the_exact_commit(self) -> None:
+        publisher = PUBLISH.GiteaReleasePublisher(
+            base_url="https://git.example.test",
+            owner="GovOPlaN",
+            repo="govoplan",
+            token="secret",
+        )
+        target = "1" * 40
+        requests: list[tuple[str, dict[str, object] | None]] = []
+
+        def request(method: str, _url: str, **kwargs):
+            payload = kwargs.get("payload")
+            requests.append((method, payload))
+            if method == "GET":
+                raise HTTPError(_url, 404, "not found", {}, None)
+            return {"id": 1}
+
+        with (
+            patch.object(
+                publisher,
+                "_resolve_commit",
+                side_effect=(target, None, target),
+            ),
+            patch.object(publisher, "_json", side_effect=request),
+        ):
+            release = publisher.release(
+                tag="v1.2.3",
+                target_commit=target,
+                title="Release",
+                body="Body",
+            )
+
+        self.assertEqual({"id": 1}, release)
+        self.assertEqual("POST", requests[-1][0])
+        assert requests[-1][1] is not None
+        self.assertEqual(target, requests[-1][1]["target_commitish"])
+
     def test_resolves_platforms_and_builds_evidence_descriptor(self) -> None:
         index = {
             "schemaVersion": 2,
diff --git a/tools/release/publish-runtime-release.py b/tools/release/publish-runtime-release.py
index 1ea099a..36e1179 100644
--- a/tools/release/publish-runtime-release.py
+++ b/tools/release/publish-runtime-release.py
@@ -9,6 +9,7 @@ import json
 import mimetypes
 import os
 from pathlib import Path
+import re
 import secrets
 import sys
 from typing import Any
@@ -18,6 +19,7 @@ from urllib.request import Request, urlopen
 
 
 MAX_ASSET_BYTES = 256 * 1024 * 1024
+COMMIT_SHA = re.compile(r"^[0-9a-f]{40}$")
 
 
 class PublishError(RuntimeError):
@@ -30,6 +32,7 @@ def build_parser() -> argparse.ArgumentParser:
     parser.add_argument("--owner", default="GovOPlaN")
     parser.add_argument("--repo", default="govoplan")
     parser.add_argument("--tag", required=True)
+    parser.add_argument("--target-commit", required=True)
     parser.add_argument("--title", required=True)
     parser.add_argument("--body", default="Signed GovOPlaN runtime distribution.")
     parser.add_argument("--asset", type=Path, action="append", default=[], required=True)
@@ -48,25 +51,49 @@ class GiteaReleasePublisher:
         self.repo = repo
         self.token = token
 
-    def release(self, *, tag: str, title: str, body: str) -> dict[str, Any]:
+    def release(
+        self,
+        *,
+        tag: str,
+        target_commit: str,
+        title: str,
+        body: str,
+    ) -> dict[str, Any]:
+        if COMMIT_SHA.fullmatch(target_commit) is None:
+            raise PublishError("release target must be an exact lowercase commit SHA")
+        resolved_target = self._resolve_commit(target_commit)
+        if resolved_target != target_commit:
+            raise PublishError("release target did not resolve to the requested commit")
+        existing_tag = self._resolve_commit(tag, allow_missing=True)
+        if existing_tag is not None and existing_tag != target_commit:
+            raise PublishError(
+                f"release tag {tag!r} already points to another commit"
+            )
+
         path = self._repo_path(f"/releases/tags/{quote(tag, safe='')}")
         try:
-            return self._json("GET", path)
+            release = self._json("GET", path)
         except HTTPError as exc:
             if exc.code != 404:
                 raise
-        return self._json(
-            "POST",
-            self._repo_path("/releases"),
-            payload={
-                "tag_name": tag,
-                "name": title,
-                "body": body,
-                "draft": False,
-                "prerelease": False,
-            },
-            expected=201,
-        )
+            release = self._json(
+                "POST",
+                self._repo_path("/releases"),
+                payload={
+                    "tag_name": tag,
+                    "target_commitish": target_commit,
+                    "name": title,
+                    "body": body,
+                    "draft": False,
+                    "prerelease": False,
+                },
+                expected=201,
+            )
+        if self._resolve_commit(tag) != target_commit:
+            raise PublishError(
+                f"release tag {tag!r} does not resolve to the requested commit"
+            )
+        return release
 
     def upload_assets(self, release: dict[str, Any], assets: tuple[Path, ...]) -> None:
         release_id = release.get("id")
@@ -165,6 +192,21 @@ class GiteaReleasePublisher:
     def _headers(self) -> dict[str, str]:
         return {"Authorization": f"token {self.token}", "Accept": "application/json"}
 
+    def _resolve_commit(self, ref: str, *, allow_missing: bool = False) -> str | None:
+        path = self._repo_path(f"/git/commits/{quote(ref, safe='')}")
+        try:
+            commit = self._json("GET", path)
+        except HTTPError as exc:
+            if allow_missing and exc.code == 404:
+                return None
+            raise
+        if not isinstance(commit, dict):
+            raise PublishError(f"Gitea returned an invalid commit for {ref!r}")
+        sha = commit.get("sha")
+        if not isinstance(sha, str) or COMMIT_SHA.fullmatch(sha) is None:
+            raise PublishError(f"Gitea returned an invalid commit SHA for {ref!r}")
+        return sha
+
     def _repo_path(self, suffix: str) -> str:
         return (
             f"{self.base_url}/api/v1/repos/{quote(self.owner, safe='')}/"
@@ -189,7 +231,12 @@ def main() -> int:
             repo=args.repo,
             token=os.environ.get(args.token_env, ""),
         )
-        release = publisher.release(tag=args.tag, title=args.title, body=args.body)
+        release = publisher.release(
+            tag=args.tag,
+            target_commit=args.target_commit,
+            title=args.title,
+            body=args.body,
+        )
         publisher.upload_assets(release, tuple(args.asset))
     except (HTTPError, OSError, PublishError, ValueError) as exc:
         print(f"error: {exc}", file=sys.stderr)
diff --git a/tools/release/runtime/nginx.conf b/tools/release/runtime/nginx.conf
index 2ddf20f..36d9668 100644
--- a/tools/release/runtime/nginx.conf
+++ b/tools/release/runtime/nginx.conf
@@ -13,7 +13,10 @@ http {
     sendfile on;
     server_tokens off;
     client_body_temp_path /tmp/client_temp;
+    fastcgi_temp_path /tmp/fastcgi_temp;
     proxy_temp_path /tmp/proxy_temp;
+    scgi_temp_path /tmp/scgi_temp;
+    uwsgi_temp_path /tmp/uwsgi_temp;
 
     map $http_x_forwarded_proto $govoplan_forwarded_proto {
         default $scheme;