diff --git a/.forgejo/workflows/bump-libmpv.yml b/.forgejo/workflows/bump-libmpv.yml
new file mode 100644
index 0000000..71a3865
--- /dev/null
+++ b/.forgejo/workflows/bump-libmpv.yml
@@ -0,0 +1,24 @@
+name: "Bump the Windows build's libmpv"
+
+on:
+    schedule:
+        - cron: "0 6 * * 1"
+    workflow_dispatch:
+
+jobs:
+    bump-libmpv:
+        runs-on: ["small", "debian-13-x86_64"]
+
+        steps:
+            - name: Checkout repository
+              uses: actions/checkout@v6
+
+            - name: Lix GHA Installer Action
+              uses: samueldr/lix-gha-installer-action@v2026-02-22
+              with:
+                  extra_nix_config: experimental-features = nix-command flakes flake-self-attrs
+
+            - name: Open a PR if there's a newer libmpv build
+              env:
+                  TOKEN: ${{ secrets.GITHUB_TOKEN }}
+              run: nix run .#bump-libmpv
diff --git a/linux/nix/bump_libmpv.sh b/linux/nix/bump_libmpv.sh
new file mode 100644
index 0000000..02a74f1
--- /dev/null
+++ b/linux/nix/bump_libmpv.sh
@@ -0,0 +1,60 @@
+# shellcheck shell=bash
+
+# Opens a PR bumping the libmpv build that the Windows CI downloads, if
+# mpv-winbuild-cmake has published a newer one. Run it from the repo root, with
+# TOKEN set to a Forgejo token that can push branches and open PRs.
+
+# Checked first, so that nothing is pushed if the PR can't be opened
+: "${TOKEN:?needs a Forgejo token}"
+: "${GITHUB_SERVER_URL:?is set by Forgejo Actions}"
+: "${GITHUB_REPOSITORY:?is set by Forgejo Actions}"
+: "${GITHUB_REF_NAME:?is set by Forgejo Actions}"
+
+workflow=.github/workflows/windows.yml
+current_url=$(grep -oE 'https://github\.com/shinchiro/mpv-winbuild-cmake/releases/download/[^"]+\.7z' "$workflow")
+current_hash=$(grep -oE -- '-ne "[0-9a-f]{64}"' "$workflow" | grep -oE '[0-9a-f]{64}')
+
+release=$(curl -fsSL https://api.github.com/repos/shinchiro/mpv-winbuild-cmake/releases/latest)
+tag=$(jq -r .tag_name <<<"$release")
+url=$(jq -r '.assets[] | select(.name | test("^mpv-dev-x86_64-[0-9]{8}-git-[0-9a-f]+\\.7z$")) | .browser_download_url' <<<"$release")
+
+if [ -z "$url" ]; then
+    echo "Release $tag has no x86_64 libmpv archive" >&2
+    exit 1
+fi
+if [ "$url" = "$current_url" ]; then
+    echo "libmpv is up to date ($tag)"
+    exit 0
+fi
+
+branch="bump-libmpv-$tag"
+if git ls-remote --exit-code --heads origin "$branch" >/dev/null; then
+    echo "$branch already exists, so its PR should already be open"
+    exit 0
+fi
+
+archive=$(mktemp)
+curl -fsSL "$url" -o "$archive"
+hash=$(sha256sum "$archive" | cut -d " " -f 1)
+rm "$archive"
+
+sed -i "s|$current_url|$url|; s|$current_hash|$hash|" "$workflow"
+
+git config user.name "Forgejo Actions"
+git config user.email "forgejo-actions@noreply.git.federated.nexus"
+git switch -c "$branch"
+git commit -am "bump libmpv to $tag"
+git push origin "$branch"
+
+curl -fsS -X POST "$GITHUB_SERVER_URL/api/v1/repos/$GITHUB_REPOSITORY/pulls" \
+    -H "Authorization: token $TOKEN" \
+    -H "Content-Type: application/json" \
+    -d "$(jq -n \
+        --arg head "$branch" \
+        --arg base "$GITHUB_REF_NAME" \
+        --arg title "Bump libmpv to $tag" \
+        --arg body "Updates the libmpv build that the Windows CI bundles to [$tag](https://github.com/shinchiro/mpv-winbuild-cmake/releases/tag/$tag)." \
+        '{head: $head, base: $base, title: $title, body: $body}')" \
+    >/dev/null
+
+echo "Opened a PR bumping libmpv to $tag"
diff --git a/linux/nix/default.nix b/linux/nix/default.nix
index 3d3b395..4fc6983 100644
--- a/linux/nix/default.nix
+++ b/linux/nix/default.nix
@@ -78,6 +78,24 @@
             program = lib.getExe e2e;
           };
 
+          bump-libmpv = {
+            type = "app";
+            program = lib.getExe (
+              pkgs.writeShellApplication {
+                name = "nexus-bump-libmpv";
+                runtimeInputs = with pkgs; [
+                  coreutils
+                  curl
+                  git
+                  gnugrep
+                  gnused
+                  jq
+                ];
+                text = builtins.readFile ./bump_libmpv.sh;
+              }
+            );
+          };
+
           e2e-headless = {
             type = "app";
             program = lib.getExe (