diff --git a/.github/workflows/advisories.yml b/.github/workflows/advisories.yml
new file mode 100644
index 0000000..d49703a
--- /dev/null
+++ b/.github/workflows/advisories.yml
@@ -0,0 +1,32 @@
+name: Dependency advisories
+on:
+  schedule:
+    - cron: '41 6 * * *'
+  workflow_dispatch:
+permissions:
+  contents: read
+concurrency:
+  group: client-dependency-advisories
+  cancel-in-progress: true
+jobs:
+  advisories:
+    if: github.ref == 'refs/heads/main'
+    name: Main branch advisories
+    runs-on: ubuntu-24.04
+    timeout-minutes: 10
+    steps:
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          persist-credentials: false
+      - name: Install pinned cargo-deny
+        run: |
+          install -d "${RUNNER_TEMP}/tools/cargo-deny" "${RUNNER_TEMP}/bin"
+          curl --fail --silent --show-error --location https://github.com/EmbarkStudios/cargo-deny/releases/download/0.20.2/cargo-deny-0.20.2-x86_64-unknown-linux-musl.tar.gz --output "${RUNNER_TEMP}/cargo-deny.tar.gz"
+          printf '%s  %s\n' 9f12ed4c49936e09b48bf862b595cde2fe64fcbd9d74dfacac6131ca824c8d5f "${RUNNER_TEMP}/cargo-deny.tar.gz" | sha256sum --check --strict
+          tar -xzf "${RUNNER_TEMP}/cargo-deny.tar.gz" -C "${RUNNER_TEMP}/tools/cargo-deny" --strip-components=1
+          install "${RUNNER_TEMP}/tools/cargo-deny/cargo-deny" "${RUNNER_TEMP}/bin/cargo-deny"
+          echo "${RUNNER_TEMP}/bin" >>"${GITHUB_PATH}"
+      - run: rustup toolchain install 1.97.1 --profile minimal
+      # Pull requests only fail on advisories they introduce, so this is where
+      # a newly published advisory against main's Cargo.lock shows up.
+      - run: tools/check-advisories.sh
diff --git a/.github/workflows/validate.yml b/.github/workflows/validate.yml
index d9a4e15..75e42a8 100644
--- a/.github/workflows/validate.yml
+++ b/.github/workflows/validate.yml
@@ -40,6 +40,8 @@ jobs:
           tar -xzf "${RUNNER_TEMP}/syft.tar.gz" -C "${RUNNER_TEMP}/bin" syft
           echo "${RUNNER_TEMP}/bin" >>"${GITHUB_PATH}"
       - run: tools/validate.sh
+        env:
+          ADVISORY_BASE_REVISION: ${{ github.event.pull_request.base.sha }}
 
   windows:
     name: Windows build and tests
diff --git a/README.md b/README.md
index 375f3a9..ffefc3e 100644
--- a/README.md
+++ b/README.md
@@ -74,7 +74,9 @@ SDL_VIDEODRIVER=dummy cargo run --locked --package atrinik-client -- window
 
 Run `tools/validate.sh` for formatting, Clippy-as-errors, tests, architecture,
 provenance/parity, dependency/license/advisory, native-library, release, SBOM,
-and reproducibility gates.
+and reproducibility gates. On pull requests, `ADVISORY_BASE_REVISION` limits
+the advisory gate to advisories the change introduces; ones already on `main`
+are warnings there and fail the daily `Dependency advisories` workflow instead.
 
 Semantic-release creates an immutable version tag from `main` without exposing
 a partial GitHub release. A completion-triggered workflow resolves that exact
diff --git a/tools/check-advisories.sh b/tools/check-advisories.sh
new file mode 100755
index 0000000..91f7787
--- /dev/null
+++ b/tools/check-advisories.sh
@@ -0,0 +1,73 @@
+#!/usr/bin/env bash
+# Copyright (c) 2026 Atrinik contributors. SPDX-License-Identifier: MIT
+#
+# Fail on RustSec advisories that this change introduces. With
+# ADVISORY_BASE_REVISION set (pull requests), advisories already present at
+# that revision are reported as warnings so an advisory published against
+# main does not fail unrelated pull requests. Without it (main, local runs,
+# dependency candidates) every advisory fails.
+set -euo pipefail
+repository=$(git rev-parse --show-toplevel)
+cd "${repository}"
+
+# Prints one "ID:crate@version" key per denied finding. Yanked crates carry no
+# advisory ID, so the crate coordinates keep distinct findings distinct.
+advisory_ids() {
+  local directory=$1 output status=0
+  output=$(mktemp)
+  (cd "${directory}" && cargo deny --locked --format json check advisories 2>"${output}" >/dev/null) || status=$?
+  python3 - "${output}" "${status}" <<'PY' || { rm -f -- "${output}"; return 1; }
+import json, sys
+keys, summary = set(), False
+for line in open(sys.argv[1], encoding='utf-8'):
+    try:
+        entry = json.loads(line)
+    except json.JSONDecodeError:
+        continue
+    fields = entry.get('fields', {})
+    if entry.get('type') == 'summary':
+        summary = True
+    elif entry.get('type') == 'diagnostic' and fields.get('severity') == 'error':
+        advisory = fields.get('advisory') or {}
+        crates = [graph.get('Krate') or {} for graph in fields.get('graphs') or []]
+        coordinates = ','.join(sorted(f"{krate.get('name')}@{krate.get('version')}" for krate in crates)) or 'unknown'
+        keys.add(f"{advisory.get('id') or fields.get('code') or 'unknown'}:{coordinates}")
+# A non-zero exit is only an advisory result when cargo-deny completed its
+# check and reported the findings; anything else is an operational failure.
+if int(sys.argv[2]) != 0 and not (summary and keys):
+    sys.exit(f'cargo-deny advisories check failed (exit {sys.argv[2]}) without reporting advisories:\n'
+             + open(sys.argv[1], encoding='utf-8').read()[-4000:])
+print('\n'.join(sorted(keys)))
+PY
+  rm -f -- "${output}"
+}
+
+head_ids=$(advisory_ids .) || exit 1
+if [ -z "${head_ids}" ]; then
+  echo "advisories ok"
+  exit 0
+fi
+
+base=${ADVISORY_BASE_REVISION:-}
+if [ -z "${base}" ]; then
+  cargo deny --locked check advisories
+  exit 1
+fi
+
+worktree=$(mktemp -d /tmp/atrinik-client-advisory-base.XXXXXX)
+trap 'git worktree remove --force "${worktree}" >/dev/null 2>&1 || rm -rf -- "${worktree}"' EXIT
+git worktree add --detach --quiet "${worktree}" "${base}"
+base_ids=$(advisory_ids "${worktree}") || exit 1
+
+introduced=$(comm -23 <(printf '%s\n' "${head_ids}") <(printf '%s\n' "${base_ids}" | sed '/^$/d'))
+if [ -n "${introduced}" ]; then
+  echo "advisories introduced by this change:" >&2
+  printf '  %s\n' ${introduced} >&2
+  cargo deny --locked check advisories
+  exit 1
+fi
+
+for id in ${head_ids}; do
+  echo "::warning title=Pre-existing dependency advisory::${id} is already present on the base revision; fix it on main (see tools/check-advisories.sh)."
+done
+echo "advisories present on base only: $(echo ${head_ids})"
diff --git a/tools/validate.sh b/tools/validate.sh
index a2a1cdb..983922a 100755
--- a/tools/validate.sh
+++ b/tools/validate.sh
@@ -12,7 +12,8 @@ cargo fmt --all --check
 cargo clippy --locked --workspace --all-targets -- -D warnings
 cargo test --locked --workspace --all-targets
 cargo test --locked --workspace --doc
-cargo deny --locked check
+cargo deny --locked check bans licenses sources
+tools/check-advisories.sh
 tools/check-foundations.sh
 cargo run --locked --quiet --package atrinik-client -- version
 cargo run --locked --quiet --package atrinik-client -- headless