diff --git a/backend/src/app/rpc/commands/fonts.clj b/backend/src/app/rpc/commands/fonts.clj
index 0ca38ae7fd..6f9f9bb109 100644
--- a/backend/src/app/rpc/commands/fonts.clj
+++ b/backend/src/app/rpc/commands/fonts.clj
@@ -93,6 +93,18 @@
 
 (declare create-font-variant)
 
+(defn- check-font-team-ownership!
+  "When font-id already has variants belonging to a different team,
+  raises :not-found to prevent cross-team font injection."
+  [conn team-id font-id]
+  (let [row (db/get* conn :team-font-variant
+                     {:font-id font-id}
+                     {::db/columns [:team-id]})]
+    (when (and row (not= (:team-id row) team-id))
+      (ex/raise :type :not-found
+                :code :object-not-found
+                :hint "font does not belong to this team"))))
+
 (def ^:private schema:create-font-variant
   [:map {:title "create-font-variant"}
    [:team-id    ::sm/uuid]
@@ -132,8 +144,9 @@
                 [:process-font/global]]
    ::webhooks/event? true
    ::sm/params schema:create-font-variant}
-  [{:keys [::db/pool] :as cfg} {:keys [::rpc/profile-id team-id] :as params}]
+  [{:keys [::db/pool] :as cfg} {:keys [::rpc/profile-id team-id font-id uploads] :as params}]
   (teams/check-edition-permissions! pool profile-id team-id)
+  (check-font-team-ownership! pool team-id font-id)
   (quotes/check! cfg {::quotes/id ::quotes/font-variants-per-team
                       ::quotes/profile-id profile-id
                       ::quotes/team-id team-id})
diff --git a/backend/test/backend_tests/rpc_font_test.clj b/backend/test/backend_tests/rpc_font_test.clj
index 4f4b5378f7..fc771ebbf1 100644
--- a/backend/test/backend_tests/rpc_font_test.clj
+++ b/backend/test/backend_tests/rpc_font_test.clj
@@ -608,3 +608,43 @@
                     :name "Valid Font Name"}
             out    (th/command! params)]
         (t/is (th/success? out))))))
+
+(t/deftest create-font-variant-rejects-foreign-font-id
+  ;; N2-07: A user with edit permissions on their own team must not be
+  ;; able to create a font variant using a font-id that already belongs
+  ;; to another team (BOLA / CWE-639).
+  (with-mocks [mock {:target 'app.rpc.quotes/check! :return nil}]
+    (let [prof1   (th/create-profile* 1 {:is-active true})
+          prof2   (th/create-profile* 2 {:is-active true})
+          team1   (:default-team-id prof1)
+          team2   (:default-team-id prof2)
+          font-id (uuid/custom 10 999)
+          data    (-> (io/resource "backend_tests/test_files/font-1.ttf")
+                      (io/read*))]
+
+      ;; prof1 creates a font variant in team1 with font-id
+      (let [params {::th/type :create-font-variant
+                    ::rpc/profile-id (:id prof1)
+                    :team-id     team1
+                    :font-id     font-id
+                    :font-family "SharedFont"
+                    :font-weight 400
+                    :font-style  "normal"
+                    :data        {"font/ttf" data}}
+            out    (th/command! params)]
+        (t/is (nil? (:error out))))
+
+      ;; prof2 tries to create a variant using the same font-id but
+      ;; in team2 — must be rejected because font-id belongs to team1
+      (let [params {::th/type :create-font-variant
+                    ::rpc/profile-id (:id prof2)
+                    :team-id     team2
+                    :font-id     font-id
+                    :font-family "SharedFont"
+                    :font-weight 700
+                    :font-style  "normal"
+                    :data        {"font/ttf" data}}
+            out    (th/command! params)]
+        (t/is (some? (:error out)))
+        (t/is (= :not-found (-> out :error ex-data :type)))
+        (t/is (= :object-not-found (-> out :error ex-data :code)))))))