diff --git a/apps/backend/services/metrics_service.py b/apps/backend/services/metrics_service.py
index 5c7abfe2..5c5ea4eb 100644
--- a/apps/backend/services/metrics_service.py
+++ b/apps/backend/services/metrics_service.py
@@ -53,6 +53,7 @@
 from models.scan import SCAN_STATUS_VALUES, VULN_SEVERITY_VALUES
 from models.task_run import TaskRun
 from services.policy_gate import _CLOSED_FINDING_STATUSES
+from services.trivy_health_service import get_trivy_db_status_cached
 
 log = structlog.get_logger("services.metrics")
 
@@ -177,6 +178,36 @@ async def _task_run_last_recorded(session: AsyncSession) -> float:
     return newest.timestamp() if newest else 0.0
 
 
+
+def _vuln_db_freshness() -> tuple[float, float]:
+    """When the vulnerability database was last updated, and our refresh gap.
+
+    Two values because neither answers the question alone. The timestamp says
+    when the data stopped changing; the interval says how long that is
+    supposed to be able to go on. A collector that has both can decide
+    staleness for the deployment it is watching, which is the only place that
+    decision can be made correctly: schedules differ, and an air-gapped
+    install that mirrors the database on a slower cadence is not broken.
+
+    No threshold is computed here, and the panel's own fresh / stale
+    classification is deliberately not published. That bucketing exists for a
+    screen somebody is looking at; a series carrying it would freeze one
+    judgement into the metric and make the collector's own rule unreachable.
+
+    Reads the cached snapshot. The uncached read touches the filesystem, and
+    this runs on every scrape.
+
+    Returns ``(0.0, interval)`` when no database has been downloaded yet.
+    Zero is distinguishable from any real timestamp and keeps the series
+    present, which matters: a missing series draws nothing on a dashboard and
+    reads as nothing being wrong, and "no database at all" is the worst state
+    this can be in.
+    """
+    status = get_trivy_db_status_cached()
+    last_update = status.last_update.timestamp() if status.last_update else 0.0
+    return last_update, float(status.refresh_interval_hours)
+
+
 async def render_metrics(session: AsyncSession) -> str:
     """The whole document, in the order the contract file lists it.
 
@@ -320,6 +351,29 @@ async def render_metrics(session: AsyncSession) -> str:
             )
         )
 
+    vuln_db_last_update, vuln_db_interval_hours = await asyncio.to_thread(
+        _vuln_db_freshness
+    )
+    document.append(
+        _block(
+            "trusca_vuln_db_last_update_timestamp_seconds",
+            "Unix time the vulnerability database was last updated upstream; "
+            "0 when none has been downloaded. Scans keep succeeding against a "
+            "stale database, so nothing else reports this.",
+            "gauge",
+            [({}, vuln_db_last_update)],
+        )
+    )
+    document.append(
+        _block(
+            "trusca_vuln_db_refresh_interval_hours",
+            "Configured hours between refresh attempts. Published so a "
+            "collector can derive staleness from this deployment's own "
+            "cadence rather than a threshold baked in here.",
+            "gauge",
+            [({}, vuln_db_interval_hours)],
+        )
+    )
     document.append(
         _block(
             "trusca_task_runs_last_recorded_timestamp_seconds",
diff --git a/apps/backend/tests/unit/services/test_vuln_db_freshness_metric.py b/apps/backend/tests/unit/services/test_vuln_db_freshness_metric.py
new file mode 100644
index 00000000..356af79a
--- /dev/null
+++ b/apps/backend/tests/unit/services/test_vuln_db_freshness_metric.py
@@ -0,0 +1,131 @@
+# SPDX-License-Identifier: Apache-2.0
+# Copyright 2026 TRUSCA contributors
+"""The vulnerability-database freshness series, and what it refuses to decide.
+
+A database that stopped updating does not make scans fail. They keep running,
+keep finding the vulnerabilities it knew about when it stopped, and report
+success. Nothing in the system objects. That is the whole reason for a series
+here rather than a check somewhere.
+
+Two things are asserted beyond the happy path. The series stays present when
+no database exists at all, because a missing series draws nothing and reads as
+nothing being wrong. And no staleness verdict is published, because the
+deployment's own refresh cadence is the only correct basis for one and that
+lives in the collector.
+"""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+from datetime import UTC, datetime
+from typing import Any
+
+import pytest
+
+from services import metrics_service
+
+
+@dataclass
+class _Status:
+    """Only the two fields the metric reads."""
+
+    last_update: datetime | None
+    refresh_interval_hours: int
+
+
+@pytest.fixture
+def status(monkeypatch: pytest.MonkeyPatch) -> Any:
+    def _install(snapshot: _Status) -> None:
+        monkeypatch.setattr(
+            metrics_service, "get_trivy_db_status_cached", lambda: snapshot
+        )
+
+    return _install
+
+
+def test_the_last_update_is_published_as_unix_time(status: Any) -> None:
+    moment = datetime(2026, 7, 18, 12, 57, 54, tzinfo=UTC)
+    status(_Status(last_update=moment, refresh_interval_hours=168))
+
+    last_update, _ = metrics_service._vuln_db_freshness()
+
+    assert last_update == moment.timestamp()
+
+
+def test_the_configured_interval_is_published_beside_it(status: Any) -> None:
+    """The collector needs both to decide anything.
+
+    The timestamp says when the data stopped changing; the interval says how
+    long that is supposed to be able to go on. An air-gapped install mirroring
+    on a slower cadence is not broken, and only the interval distinguishes it
+    from one that is.
+    """
+    status(_Status(last_update=datetime.now(UTC), refresh_interval_hours=168))
+
+    _, interval = metrics_service._vuln_db_freshness()
+
+    assert interval == 168.0
+
+
+def test_no_database_still_publishes_the_series(status: Any) -> None:
+    """Zero, not an absent series.
+
+    "No database has ever been downloaded" is the worst state this can be in,
+    and it is exactly the state where a series that disappeared would leave a
+    dashboard looking clean.
+    """
+    status(_Status(last_update=None, refresh_interval_hours=168))
+
+    last_update, interval = metrics_service._vuln_db_freshness()
+
+    assert last_update == 0.0
+    assert interval == 168.0
+
+
+def test_a_long_stale_database_is_reported_as_a_plain_timestamp(
+    status: Any,
+) -> None:
+    """No verdict, no clamping, no special value for "too old".
+
+    A real deployment was found 46 days behind while every scan succeeded. The
+    series reports the timestamp it has; whether 46 days is a problem depends
+    on the refresh cadence, which is why that is published alongside rather
+    than folded into a judgement here.
+    """
+    stale = datetime(2026, 7, 18, 12, 57, 54, tzinfo=UTC)
+    status(_Status(last_update=stale, refresh_interval_hours=168))
+
+    last_update, _ = metrics_service._vuln_db_freshness()
+
+    assert last_update == stale.timestamp()
+
+
+def test_the_accessor_never_reads_the_panel_s_verdict() -> None:
+    """The fresh / stale bucket the snapshot carries is not published.
+
+    That classification exists for a screen. A series carrying it would freeze
+    one judgement into the metric and put it beyond the collector's reach: a
+    deployment cannot override a label it is handed, and the right threshold
+    depends on a refresh cadence only the deployment knows.
+
+    Asserted on the attribute access rather than on words in the source. The
+    first two versions of this test matched the strings "freshness" and
+    "fresh", and both failed on names that legitimately contain them: the
+    accessor is named for what it measures, and "refresh" contains "fresh".
+    A test of spelling is not a test of behaviour.
+    """
+    import ast
+    import inspect
+
+    tree = ast.parse(inspect.getsource(metrics_service._vuln_db_freshness))
+    read = {
+        node.attr
+        for node in ast.walk(tree)
+        if isinstance(node, ast.Attribute)
+    }
+
+    assert "freshness" not in read, (
+        "the metric reads the snapshot's freshness bucket; publish the "
+        "timestamp and the interval and let the collector decide"
+    )
+    assert read >= {"last_update", "refresh_interval_hours"}
diff --git a/docs-site/docs/admin-guide/disk-and-health.md b/docs-site/docs/admin-guide/disk-and-health.md
index ebfd0c18..fa6586a1 100644
--- a/docs-site/docs/admin-guide/disk-and-health.md
+++ b/docs-site/docs/admin-guide/disk-and-health.md
@@ -204,6 +204,8 @@ What it publishes is a fixed list of aggregate counts:
 | `trusca_task_runs_24h` | `task`, `outcome` | Background task runs in the last day. `outcome=running` counts runs that started and never reported an end |
 | `trusca_task_run_duration_seconds_p50_24h` | `task` | Median duration of runs that finished in the last day |
 | `trusca_task_run_duration_seconds_p95_24h` | `task` | Same at the 95th percentile |
+| `trusca_vuln_db_last_update_timestamp_seconds` | | Unix time the vulnerability database was last updated upstream, `0` when none has been downloaded |
+| `trusca_vuln_db_refresh_interval_hours` | | Configured hours between refresh attempts |
 | `trusca_task_runs_last_recorded_timestamp_seconds` | | Unix time of the newest task-run row, `0` when the table is empty |
 
 No project, package, repository or person's name appears anywhere in the
@@ -215,6 +217,20 @@ Task history is swept on a retention schedule, so a cumulative count would go
 down when the sweep runs and a collector reads a falling counter as a restart.
 The window is in the name because changing it changes what the series means.
 
+The two vulnerability-database series belong together: the timestamp says when
+the data stopped changing, the interval says how long that is supposed to be
+able to go on. Neither answers on its own, because an air-gapped install
+mirroring on a slower cadence is not broken and only the interval separates it
+from one that is. No staleness verdict ships in the metrics, and the fresh /
+stale wording the panel uses is deliberately not published: that bucketing is
+for a screen somebody is reading, and a series carrying it would put the
+judgement beyond your collector's reach.
+
+This one deserves an alert because a stale database is silent. Scans keep
+running, keep finding what the database knew when it stopped, and report
+success. One deployment was found 46 days behind with every scan green, and
+what surfaced it was somebody looking at the disk for an unrelated reason.
+
 `trusca_task_runs_last_recorded_timestamp_seconds` is worth an alert of its
 own. It watches the recorder rather than the work: recording history is
 designed never to fail a task, so a missing database grant or an unrun
diff --git a/docs-site/i18n/ko/docusaurus-plugin-content-docs/current/admin-guide/disk-and-health.md b/docs-site/i18n/ko/docusaurus-plugin-content-docs/current/admin-guide/disk-and-health.md
index 166392bf..672330f9 100644
--- a/docs-site/i18n/ko/docusaurus-plugin-content-docs/current/admin-guide/disk-and-health.md
+++ b/docs-site/i18n/ko/docusaurus-plugin-content-docs/current/admin-guide/disk-and-health.md
@@ -199,6 +199,8 @@ docker-compose -f docker-compose.yml exec backend \
 | `trusca_task_runs_24h` | `task`, `outcome` | 최근 하루 동안의 배경 작업 실행 수. `outcome=running`은 시작한 뒤 종료를 보고하지 않은 실행입니다 |
 | `trusca_task_run_duration_seconds_p50_24h` | `task` | 최근 하루 동안 끝난 실행의 소요 시간 중앙값 |
 | `trusca_task_run_duration_seconds_p95_24h` | `task` | 같은 값의 95 백분위수 |
+| `trusca_vuln_db_last_update_timestamp_seconds` | | 취약점 데이터베이스가 업스트림에서 마지막으로 갱신된 유닉스 시각. 내려받은 적이 없으면 `0` |
+| `trusca_vuln_db_refresh_interval_hours` | | 설정된 갱신 시도 간격(시간) |
 | `trusca_task_runs_last_recorded_timestamp_seconds` | | 가장 최근 작업 이력 행의 유닉스 시각. 테이블이 비어 있으면 `0` |
 
 프로젝트·패키지·저장소·사람 이름은 출력 어디에도 나오지 않습니다. 목록은
@@ -210,6 +212,16 @@ docker-compose -f docker-compose.yml exec backend \
 카운터를 프로세스 재시작으로 읽습니다. 창 길이를 이름에 넣은 이유는 창이 바뀌면 계열의
 뜻이 달라지기 때문입니다.
 
+취약점 데이터베이스 계열 둘은 함께 봐야 합니다. 시각은 데이터가 언제 멈췄는지를, 간격은 그
+상태가 얼마나 지속돼도 되는지를 말합니다. 하나만으로는 판단할 수 없습니다. 폐쇄망에서 더 성긴
+주기로 미러링하는 배포는 고장이 아니고, 그것과 실제로 멈춘 배포를 가르는 것이 간격이기
+때문입니다. 지표에는 신선도 판정을 넣지 않습니다. 관리자 화면이 쓰는 fresh·stale 구분은
+사람이 보는 화면을 위한 것이고, 계열에 담으면 그 판단이 수집기 손을 벗어납니다.
+
+이 값에 경보가 필요한 이유는 낡은 데이터베이스가 조용하기 때문입니다. 스캔은 계속 돌고,
+데이터베이스가 멈춘 시점에 알던 것을 계속 찾아내고, 성공을 보고합니다. 어느 배포는 46일
+뒤처진 채로 모든 스캔이 정상이었고, 그것을 드러낸 것은 다른 일로 디스크를 살펴보던 사람이었습니다.
+
 `trusca_task_runs_last_recorded_timestamp_seconds`에는 별도 경보를 걸어 둘 만합니다.
 이 값은 작업이 아니라 기록 장치를 봅니다. 이력 기록은 작업을 실패시키지 않도록 설계돼
 있어서 데이터베이스 권한이 빠지거나 마이그레이션이 돌지 않아도 어디에도 오류가 나지
diff --git a/tests/contracts/metrics-series.json b/tests/contracts/metrics-series.json
index 23830c72..0d1c0b7b 100644
--- a/tests/contracts/metrics-series.json
+++ b/tests/contracts/metrics-series.json
@@ -88,6 +88,18 @@
       ],
       "help": "Task duration in seconds, p95 over runs that finished in the last 24h."
     },
+    {
+      "name": "trusca_vuln_db_last_update_timestamp_seconds",
+      "type": "gauge",
+      "labels": [],
+      "help": "Unix time the vulnerability database was last updated upstream; 0 when none has been downloaded. Scans keep succeeding against a stale database, so nothing else reports this."
+    },
+    {
+      "name": "trusca_vuln_db_refresh_interval_hours",
+      "type": "gauge",
+      "labels": [],
+      "help": "Configured hours between refresh attempts. Published so a collector can derive staleness from this deployment's own cadence rather than a threshold baked in here."
+    },
     {
       "name": "trusca_task_runs_last_recorded_timestamp_seconds",
       "type": "gauge",