diff --git a/docker/php/Dockerfile b/docker/php/Dockerfile
index 56abdda..7729ed9 100644
--- a/docker/php/Dockerfile
+++ b/docker/php/Dockerfile
@@ -6,8 +6,9 @@ FROM ${COMPOSER_IMAGE} AS composer
 FROM ${PHP_BASE_IMAGE}
 
 RUN set -eux; \
-    # 国内 ECS 访问 deb.debian.org（Fastly）易超时：main/updates 走阿里云镜像，security 走 TUNA（同步更及时）
-    sed -i 's|deb.debian.org/debian-security|mirrors.tuna.tsinghua.edu.cn/debian-security|g; s|deb.debian.org|mirrors.aliyun.com|g' /etc/apt/sources.list; \
+    # bullseye 已 EOL（2026-08），security 包在镜像站/archive 间迁移暂不可用：构建期去掉 security 源，
+    # 仅用 main/updates（阿里云池完好）。中期应将基础镜像升级到受支持的 Debian/PHP 版本
+    sed -i '/debian-security/d; s|deb.debian.org|mirrors.aliyun.com|g' /etc/apt/sources.list; \
     apt-get update && apt-get install -y --no-install-recommends \
         libfreetype6-dev \
         libjpeg62-turbo-dev \