diff --git a/.github/scripts/verify-tag-matches-sha.sh b/.github/scripts/verify-tag-matches-sha.sh
new file mode 100755
index 00000000..6610ff39
--- /dev/null
+++ b/.github/scripts/verify-tag-matches-sha.sh
@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+# Verifies that a git tag still resolves to the guarded commit SHA that was
+# validated by this workflow's guard job, protecting against a force-push/
+# retag race between the image build and any subsequent chart-publish or
+# release step.
+#
+# Required env vars: GH_TOKEN, REPO, TAG, GUARDED_SHA
+set -euo pipefail
+
+ref_json="$(gh api "repos/${REPO}/git/ref/tags/${TAG}" --jq '[.object.type, .object.sha] | @tsv')"
+read -r current_type current_sha <<< "$ref_json"
+if [[ "$current_type" == "tag" ]]; then
+  # Annotated tag: the ref's object.sha is the tag object, not the commit - peel it.
+  current_sha="$(gh api "repos/${REPO}/git/tags/${current_sha}" --jq .object.sha)"
+fi
+
+if [[ "$current_sha" != "$GUARDED_SHA" ]]; then
+  echo "::error::Tag '${TAG}' now points at ${current_sha}, not the guarded commit ${GUARDED_SHA} (force-pushed?). Refusing to proceed."
+  exit 1
+fi
+
+echo "Tag '${TAG}' still points at the guarded commit ${GUARDED_SHA}."
diff --git a/.github/workflows/publish-charts.yaml b/.github/workflows/publish-charts.yaml
index c0c32b2d..5839d0b0 100644
--- a/.github/workflows/publish-charts.yaml
+++ b/.github/workflows/publish-charts.yaml
@@ -1,35 +1,81 @@
 name: Publish charts
 
 on:
-  push:
-    tags:
-    - 'v*'
+  workflow_run:
+    workflows: ["Publish container image"]
+    types: [completed]
 
 jobs:
 
+  guard:
+    name: Verify image build succeeded
+    runs-on: ubuntu-latest
+    # Read-only job: only inspects workflow_run event metadata, no repo/API access needed.
+    permissions: {}
+    if: >
+      github.event.workflow_run.event == 'push' &&
+      startsWith(github.event.workflow_run.head_branch, 'v')
+    outputs:
+      tag: ${{ github.event.workflow_run.head_branch }}
+      sha: ${{ github.event.workflow_run.head_sha }}
+    steps:
+    - name: Check image build result
+      env:
+        CONCLUSION: ${{ github.event.workflow_run.conclusion }}
+        HEAD_BRANCH: ${{ github.event.workflow_run.head_branch }}
+      run: |
+        # No build-metadata (+...) suffix allowed: this tag is used verbatim as a
+        # container image tag downstream, and Docker/OCI tags cannot contain '+'.
+        semver_re='^v(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)(-((0|[1-9][0-9]*)|[0-9A-Za-z-]*[A-Za-z-][0-9A-Za-z-]*)(\.((0|[1-9][0-9]*)|[0-9A-Za-z-]*[A-Za-z-][0-9A-Za-z-]*))*)?$'
+        if ! [[ "$HEAD_BRANCH" =~ $semver_re ]]; then
+          echo "::error::Tag '$HEAD_BRANCH' is not a valid semver release tag"
+          exit 1
+        fi
+        if [[ "$CONCLUSION" != "success" ]]; then
+          echo "::error::Image build for tag $HEAD_BRANCH did not succeed (conclusion: $CONCLUSION). Refusing to publish chart."
+          exit 1
+        fi
+        echo "Image build succeeded for tag $HEAD_BRANCH"
+
   publish-ui-chart:
     name: Publish UI chart
+    needs: guard
     runs-on: ubuntu-latest
     permissions:
       contents: write
       packages: write
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683  # v4.2.2
       with:
+        ref: ${{ needs.guard.outputs.sha }}
         fetch-depth: 0
         persist-credentials: false
+
+    - name: Verify tag still points at the guarded commit
+      env:
+        GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        TAG: ${{ needs.guard.outputs.tag }}
+        GUARDED_SHA: ${{ needs.guard.outputs.sha }}
+        REPO: ${{ github.repository }}
+      run: .github/scripts/verify-tag-matches-sha.sh
+
     - id: run
+      env:
+        TAG: ${{ needs.guard.outputs.tag }}
+        REGISTRY_USERNAME: ${{ github.actor }}
+        REGISTRY_PASSWORD: ${{ secrets.GITHUB_TOKEN }}
+        REPO: ${{ github.repository }}
       run: |
         # Login to the registry:
         export registry="ghcr.io"
-        echo "${{ secrets.GITHUB_TOKEN }}" | helm registry login --username "${{ github.actor }}" --password-stdin "${registry}"
+        echo "${REGISTRY_PASSWORD}" | helm registry login --username "${REGISTRY_USERNAME}" --password-stdin "${registry}"
 
-        # Get the git version:
-        export git_version="$(git describe --tags)"
+        # Get the git version from the tag that triggered the image build:
+        export git_version="${TAG}"
 
         # Update the image reference in the chart:
         export app_version="${git_version}"
-        export app_image="${registry}/${{ github.repository }}:${app_version}"
+        export app_image="${registry}/${REPO}:${app_version}"
         yq -i '.images.ui = strenv(app_image)' charts/ui/values.yaml
 
         # Package the chart:
@@ -41,14 +87,25 @@ jobs:
         export chart_file="${chart_name}-${chart_version}.tgz"
         helm push "${chart_file}" "oci://${registry}/${{ github.repository_owner }}/charts"
 
+    - name: Verify tag still points at the guarded commit
+      env:
+        GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        TAG: ${{ needs.guard.outputs.tag }}
+        GUARDED_SHA: ${{ needs.guard.outputs.sha }}
+        REPO: ${{ github.repository }}
+      run: .github/scripts/verify-tag-matches-sha.sh
+
     - name: Create GitHub Release
       run: |
-        gh release create "${GITHUB_REF_NAME}" \
-          --repo "${{ github.repository }}" \
-          --title "osac-ui ${GITHUB_REF_NAME}" \
+        gh release create "${TAG}" \
+          --repo "${REPO}" \
+          --title "osac-ui ${TAG}" \
           --generate-notes \
-        || gh release edit "${GITHUB_REF_NAME}" \
-          --repo "${{ github.repository }}" \
-          --title "osac-ui ${GITHUB_REF_NAME}"
+          --verify-tag \
+        || gh release edit "${TAG}" \
+          --repo "${REPO}" \
+          --title "osac-ui ${TAG}"
       env:
         GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        TAG: ${{ needs.guard.outputs.tag }}
+        REPO: ${{ github.repository }}