diff --git a/app/models/oidc_refresh_token.rb b/app/models/oidc_refresh_token.rb
index de5b988..c881980 100644
--- a/app/models/oidc_refresh_token.rb
+++ b/app/models/oidc_refresh_token.rb
@@ -49,11 +49,21 @@ class OidcRefreshToken < ApplicationRecord
     update!(revoked_at: Time.current)
   end
 
-  # Revoke all refresh tokens in the same family (token rotation security)
+  # Revoke all refresh tokens in the same family (token rotation security).
+  # Also revoke every access token issued within the family: on a detected reuse
+  # attack the stolen chain's access tokens must not remain usable at /userinfo
+  # until they expire.
   def revoke_family!
     return unless token_family_id.present?
 
-    OidcRefreshToken.in_family(token_family_id).update_all(revoked_at: Time.current)
+    now = Time.current
+    family = OidcRefreshToken.in_family(token_family_id)
+    access_token_ids = family.pluck(:oidc_access_token_id).compact.uniq
+
+    family.update_all(revoked_at: now)
+    if access_token_ids.any?
+      OidcAccessToken.where(id: access_token_ids, revoked_at: nil).update_all(revoked_at: now)
+    end
   end
 
   private
diff --git a/test/controllers/oidc_refresh_token_controller_test.rb b/test/controllers/oidc_refresh_token_controller_test.rb
index 0381ae9..293255e 100644
--- a/test/controllers/oidc_refresh_token_controller_test.rb
+++ b/test/controllers/oidc_refresh_token_controller_test.rb
@@ -213,6 +213,50 @@ class OidcRefreshTokenControllerTest < ActionDispatch::IntegrationTest
     assert_equal family_id, new_refresh_token.token_family_id
   end
 
+  test "reusing a revoked refresh token revokes every access token in the family" do
+    access_token = OidcAccessToken.create!(
+      application: @application,
+      user: @user,
+      scope: "openid profile email"
+    )
+    refresh_token = OidcRefreshToken.create!(
+      application: @application,
+      user: @user,
+      oidc_access_token: access_token,
+      scope: "openid profile email"
+    )
+    family_id = refresh_token.token_family_id
+    old_plaintext = refresh_token.token
+
+    # Rotate once: the old refresh token is revoked; a new access + refresh token
+    # are issued into the same family.
+    post "/oauth/token", params: {
+      grant_type: "refresh_token",
+      refresh_token: old_plaintext,
+      client_id: @application.client_id,
+      client_secret: @client_secret
+    }
+    assert_response :success
+
+    new_refresh = OidcRefreshToken.in_family(family_id).where.not(id: refresh_token.id).first
+    new_access_token = new_refresh.oidc_access_token
+    refute new_access_token.reload.revoked?, "rotated-in access token should start active"
+
+    # Reuse the OLD (now revoked) refresh token -> rotation-attack detection.
+    post "/oauth/token", params: {
+      grant_type: "refresh_token",
+      refresh_token: old_plaintext,
+      client_id: @application.client_id,
+      client_secret: @client_secret
+    }
+    assert_response :bad_request
+
+    # Both the original and the rotated-in access token must now be revoked, so a
+    # stolen access token from anywhere in the chain stops working at /userinfo.
+    assert access_token.reload.revoked?, "original access token should be revoked"
+    assert new_access_token.reload.revoked?, "rotated-in access token should be revoked"
+  end
+
   test "userinfo endpoint works with hashed access token" do
     access_token = OidcAccessToken.create!(
       application: @application,