# Astro astro@5.15.9 — Release & Upgrade Intelligence
- **Product:** Astro (https://astro.build)
- **Version:** astro@5.15.9
- **Released:** Nov 17, 2025
- **Impact Score:** 5/10
- **Breaking Changes:** Not verified
- **Canonical Analysis:** https://changelogs.us/astro/updates/astro-5.15.9/

## Executive Summary (TL;DR)
Astro astro@5.15.9. Source highlight: Add handling of invalid encrypted props and slots in server islands.

## Bug Fixes
- Add handling of invalid encrypted props and slots in server islands.
- Improves the experimental Fonts API build log to show the number of downloaded files. This can help spotting excessive downloading because of misconfiguration
- Changes the remote protocol checks for images to require explicit authorization in order to use data URIs.
- Fixes wildcard hostname pattern matching to correctly reject hostnames without dots
- Fixes the behavior of `passthroughImageService` so it does not generate webp.
- Updated dependencies \[`9e9c528`, `0f75f6b`]:

## Upgrade Command
```bash
npm install --save-exact astro@5.15.9
```