diff --git a/scripts/update_release_info.py b/scripts/update_release_info.py
new file mode 100644
index 0000000..9e0462e
--- /dev/null
+++ b/scripts/update_release_info.py
@@ -0,0 +1,267 @@
+"""Update ATT&CK release hash metadata in mitreattack/release_info.py."""
+
+from __future__ import annotations
+
+import argparse
+import ast
+import json
+import pprint
+import re
+import subprocess
+import sys
+import urllib.error
+import urllib.parse
+import urllib.request
+from dataclasses import dataclass
+from pathlib import Path
+from typing import Any
+
+DOMAINS = ("enterprise", "mobile", "ics")
+RELEASE_INFO_PATH = Path("mitreattack/release_info.py")
+REQUIRED_ASSIGNMENTS = ("LATEST_VERSION", "STIX20", "STIX21")
+
+
+@dataclass(frozen=True)
+class ReleaseSource:
+    """GitHub release source for an ATT&CK STIX version."""
+
+    stix_version: str
+    owner: str
+    repo: str
+    tag_prefix: str
+    assignment_name: str
+
+
+RELEASE_SOURCES = (
+    ReleaseSource(
+        stix_version="2.0",
+        owner="mitre",
+        repo="cti",
+        tag_prefix="ATT&CK-v",
+        assignment_name="STIX20",
+    ),
+    ReleaseSource(
+        stix_version="2.1",
+        owner="mitre-attack",
+        repo="attack-stix-data",
+        tag_prefix="v",
+        assignment_name="STIX21",
+    ),
+)
+
+
+def main() -> None:
+    """Parse arguments and update release_info.py."""
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("version", nargs="?", help="ATT&CK release version, for example 19.1")
+    parser.add_argument(
+        "--release-info",
+        type=Path,
+        default=RELEASE_INFO_PATH,
+        help=f"Path to release_info.py. Defaults to {RELEASE_INFO_PATH}",
+    )
+    parser.add_argument("--token", default=None, help="GitHub token. Defaults to GITHUB_TOKEN if set.")
+    parser.add_argument("--dry-run", action="store_true", help="Print the updated file instead of writing it.")
+    parser.add_argument("--no-format", action="store_true", help="Skip running ruff format after writing.")
+    args = parser.parse_args()
+
+    version = args.version or fetch_latest_common_version(token=args.token)
+    hashes = fetch_release_hashes(version=version, token=args.token)
+    updated = update_release_info_source(args.release_info.read_text(), version=version, release_hashes=hashes)
+
+    if args.dry_run:
+        print(updated)
+        return
+
+    args.release_info.write_text(updated)
+    if not args.no_format:
+        subprocess.run(["uv", "run", "--extra", "dev", "ruff", "format", str(args.release_info)], check=True)
+
+    print(f"Updated {args.release_info} for ATT&CK v{version}")
+
+
+def fetch_latest_common_version(token: str | None = None) -> str:
+    """Fetch the latest non-prerelease version present in both STIX release repos."""
+    latest_versions = {source.stix_version: fetch_latest_version(source, token=token) for source in RELEASE_SOURCES}
+    if latest_versions["2.0"] != latest_versions["2.1"]:
+        raise SystemExit(
+            "Latest STIX release versions do not match: "
+            f"STIX 2.0={latest_versions['2.0']}, STIX 2.1={latest_versions['2.1']}. "
+            "Pass the desired ATT&CK version explicitly."
+        )
+    return latest_versions["2.0"]
+
+
+def fetch_latest_version(source: ReleaseSource, token: str | None = None) -> str:
+    """Fetch the latest GitHub release version for one STIX source."""
+    release = github_json(f"https://api.github.com/repos/{source.owner}/{source.repo}/releases/latest", token=token)
+    return version_from_tag(release["tag_name"], source.tag_prefix)
+
+
+def fetch_release_hashes(version: str, token: str | None = None) -> dict[str, dict[str, str]]:
+    """Fetch SHA256 hashes for every required STIX source and domain."""
+    release_hashes: dict[str, dict[str, str]] = {}
+    for source in RELEASE_SOURCES:
+        release_hashes[source.assignment_name] = fetch_source_hashes(source, version=version, token=token)
+    return release_hashes
+
+
+def fetch_source_hashes(source: ReleaseSource, version: str, token: str | None = None) -> dict[str, str]:
+    """Fetch SHA256 hashes for one STIX release source."""
+    tag = f"{source.tag_prefix}{version}"
+    url = f"https://api.github.com/repos/{source.owner}/{source.repo}/releases/tags/{quote_tag(tag)}"
+    release = github_json(url, token=token)
+    assets = release.get("assets", [])
+    hashes: dict[str, str] = {}
+
+    for domain in DOMAINS:
+        asset = find_domain_asset(assets, domain=domain, version=version)
+        digest = asset.get("digest")
+        if isinstance(digest, str) and digest.startswith("sha256:"):
+            hashes[domain] = digest.removeprefix("sha256:")
+            continue
+
+        browser_download_url = asset.get("browser_download_url")
+        if not isinstance(browser_download_url, str):
+            raise SystemExit(f"Missing browser_download_url for {source.owner}/{source.repo} {tag} {asset.get('name')}")
+        hashes[domain] = fetch_sha256(browser_download_url, token=token)
+
+    return hashes
+
+
+def update_release_info_source(source: str, version: str, release_hashes: dict[str, dict[str, str]]) -> str:
+    """Return release_info.py source updated with the given ATT&CK version and hashes."""
+    tree = ast.parse(source)
+    assignments = find_assignments(tree)
+
+    stix20 = ast.literal_eval(assignments["STIX20"].value)
+    stix21 = ast.literal_eval(assignments["STIX21"].value)
+
+    for assignment_name, stix_hashes in (("STIX20", stix20), ("STIX21", stix21)):
+        for domain in DOMAINS:
+            stix_hashes[domain][version] = release_hashes[assignment_name][domain]
+
+    replacements = {
+        "LATEST_VERSION": f'LATEST_VERSION = "{version}"',
+        "STIX20": format_assignment("STIX20", stix20),
+        "STIX21": format_assignment("STIX21", stix21),
+    }
+
+    return replace_assignments(source, assignments, replacements)
+
+
+def find_assignments(tree: ast.Module) -> dict[str, ast.Assign]:
+    """Find required top-level assignment nodes."""
+    assignments: dict[str, ast.Assign] = {}
+    for node in tree.body:
+        if not isinstance(node, ast.Assign):
+            continue
+        for target in node.targets:
+            if isinstance(target, ast.Name) and target.id in REQUIRED_ASSIGNMENTS:
+                assignments[target.id] = node
+
+    missing = sorted(set(REQUIRED_ASSIGNMENTS) - set(assignments))
+    if missing:
+        raise SystemExit(f"Missing required assignment(s): {', '.join(missing)}")
+    return assignments
+
+
+def replace_assignments(source: str, assignments: dict[str, ast.Assign], replacements: dict[str, str]) -> str:
+    """Replace assignment source ranges using AST line numbers."""
+    lines = source.splitlines()
+    for name, replacement in sorted(replacements.items(), key=lambda item: assignments[item[0]].lineno, reverse=True):
+        node = assignments[name]
+        if node.end_lineno is None:
+            raise SystemExit(f"Could not determine source range for {name}")
+        lines[node.lineno - 1 : node.end_lineno] = replacement.splitlines()
+    return "\n".join(lines) + "\n"
+
+
+def format_assignment(name: str, value: Any) -> str:
+    """Format a Python assignment for release hash data."""
+    return f"{name} = {pprint.pformat(value, width=120, sort_dicts=False)}"
+
+
+def find_domain_asset(assets: list[dict[str, Any]], domain: str, version: str) -> dict[str, Any]:
+    """Find the GitHub release asset for a domain."""
+    candidate_names = {
+        f"{domain}-attack.json",
+        f"{domain}-attack-{version}.json",
+    }
+    for asset in assets:
+        if asset.get("name") in candidate_names:
+            return asset
+    raise SystemExit(
+        f"Could not find release asset for {domain}. Expected one of: {', '.join(sorted(candidate_names))}"
+    )
+
+
+def github_json(url: str, token: str | None = None) -> Any:
+    """Fetch JSON from the GitHub API."""
+    request = urllib.request.Request(url, headers=github_headers(token))
+    try:
+        with urllib.request.urlopen(request) as response:
+            return json.loads(response.read().decode("utf-8"))
+    except urllib.error.HTTPError as error:
+        raise SystemExit(f"GitHub API request failed for {url}: HTTP {error.code}") from error
+    except urllib.error.URLError as error:
+        raise SystemExit(f"GitHub API request failed for {url}: {error.reason}") from error
+
+
+def fetch_sha256(url: str, token: str | None = None) -> str:
+    """Download an asset and return its SHA256 hash."""
+    import hashlib
+
+    request = urllib.request.Request(url, headers=github_headers(token))
+    sha256_hash = hashlib.sha256()
+    try:
+        with urllib.request.urlopen(request) as response:
+            while chunk := response.read(1024 * 1024):
+                sha256_hash.update(chunk)
+    except urllib.error.HTTPError as error:
+        raise SystemExit(f"Asset download failed for {url}: HTTP {error.code}") from error
+    except urllib.error.URLError as error:
+        raise SystemExit(f"Asset download failed for {url}: {error.reason}") from error
+    return sha256_hash.hexdigest()
+
+
+def github_headers(token: str | None = None) -> dict[str, str]:
+    """Build GitHub request headers."""
+    headers = {
+        "Accept": "application/vnd.github+json",
+        "User-Agent": "mitreattack-python-release-info-updater",
+        "X-GitHub-Api-Version": "2022-11-28",
+    }
+    token = token or env_github_token()
+    if token:
+        headers["Authorization"] = f"Bearer {token}"
+    return headers
+
+
+def env_github_token() -> str | None:
+    """Return GITHUB_TOKEN from the environment without importing os at module import time."""
+    import os
+
+    return os.environ.get("GITHUB_TOKEN")
+
+
+def version_from_tag(tag: str, tag_prefix: str) -> str:
+    """Extract an ATT&CK version from a release tag."""
+    if not tag.startswith(tag_prefix):
+        raise SystemExit(f"Release tag {tag!r} does not start with expected prefix {tag_prefix!r}")
+    version = tag.removeprefix(tag_prefix)
+    if not re.fullmatch(r"\d+\.\d+(?:[-.][A-Za-z0-9]+)?", version):
+        raise SystemExit(f"Could not parse ATT&CK release version from tag {tag!r}")
+    return version
+
+
+def quote_tag(tag: str) -> str:
+    """URL-quote a release tag for GitHub API paths."""
+    return urllib.parse.quote(tag, safe="")
+
+
+if __name__ == "__main__":
+    try:
+        main()
+    except KeyboardInterrupt:
+        sys.exit(130)
diff --git a/tests/test_release_info_updater.py b/tests/test_release_info_updater.py
new file mode 100644
index 0000000..350c01d
--- /dev/null
+++ b/tests/test_release_info_updater.py
@@ -0,0 +1,82 @@
+"""Tests for the release_info.py updater script."""
+
+from __future__ import annotations
+
+import importlib.util
+import sys
+from pathlib import Path
+
+SCRIPT_PATH = Path(__file__).parents[1] / "scripts" / "update_release_info.py"
+
+
+def load_updater():
+    """Load the updater script as a test module."""
+    spec = importlib.util.spec_from_file_location("update_release_info", SCRIPT_PATH)
+    assert spec
+    assert spec.loader
+    module = importlib.util.module_from_spec(spec)
+    sys.modules["update_release_info"] = module
+    spec.loader.exec_module(module)
+    return module
+
+
+def test_update_release_info_source_updates_required_values():
+    """Updater rewrites release constants while preserving unrelated code."""
+    updater = load_updater()
+    source = '''"""Release info."""
+
+LATEST_VERSION = "1.0"
+
+STIX20 = {
+    "enterprise": {"1.0": "old-enterprise-20"},
+    "mobile": {"1.0": "old-mobile-20"},
+    "ics": {"1.0": "old-ics-20"},
+    "pre": {"1.0": "old-pre-20"},
+}
+
+STIX21 = {
+    "enterprise": {"1.0": "old-enterprise-21"},
+    "mobile": {"1.0": "old-mobile-21"},
+    "ics": {"1.0": "old-ics-21"},
+}
+
+
+def keep_me():
+    return "unchanged"
+'''
+    release_hashes = {
+        "STIX20": {
+            "enterprise": "new-enterprise-20",
+            "mobile": "new-mobile-20",
+            "ics": "new-ics-20",
+        },
+        "STIX21": {
+            "enterprise": "new-enterprise-21",
+            "mobile": "new-mobile-21",
+            "ics": "new-ics-21",
+        },
+    }
+
+    updated = updater.update_release_info_source(source, version="2.0", release_hashes=release_hashes)
+
+    assert 'LATEST_VERSION = "2.0"' in updated
+    assert "'2.0': 'new-enterprise-20'" in updated
+    assert "'2.0': 'new-mobile-20'" in updated
+    assert "'2.0': 'new-ics-20'" in updated
+    assert "'2.0': 'new-enterprise-21'" in updated
+    assert "'2.0': 'new-mobile-21'" in updated
+    assert "'2.0': 'new-ics-21'" in updated
+    assert "'pre': {'1.0': 'old-pre-20'}" in updated
+    assert 'return "unchanged"' in updated
+
+
+def test_find_domain_asset_accepts_current_and_versioned_names():
+    """Asset lookup accepts release asset naming variants from ATT&CK data repos."""
+    updater = load_updater()
+    assets = [
+        {"name": "enterprise-attack-2.0.json"},
+        {"name": "mobile-attack.json"},
+    ]
+
+    assert updater.find_domain_asset(assets, domain="enterprise", version="2.0")["name"] == "enterprise-attack-2.0.json"
+    assert updater.find_domain_asset(assets, domain="mobile", version="2.0")["name"] == "mobile-attack.json"