diff --git a/.github/workflows/build_cmake.yml b/.github/workflows/build_cmake.yml
index 23939b0..28e1222 100644
--- a/.github/workflows/build_cmake.yml
+++ b/.github/workflows/build_cmake.yml
@@ -207,8 +207,17 @@ jobs:
         if: matrix.checkout_version == 'v4'
         uses: actions/checkout@v4
 
+      # Fix Debian Jessie EOL repository issues (GCC 5-6)
+      - name: Fix Debian repositories for Jessie (GCC 5-6)
+        if: matrix.version == 5 || matrix.version == 6
+        run: |
+          # Debian Jessie reached EOL, repositories moved to archive
+          sed -i 's/deb.debian.org/archive.debian.org/g' /etc/apt/sources.list
+          sed -i 's|security.debian.org|archive.debian.org/debian-security|g' /etc/apt/sources.list
+          sed -i '/jessie-updates/d' /etc/apt/sources.list
+
       # Fix Debian Buster EOL repository issues (GCC 7-8, Clang 7-9)
-      - name: Fix Debian repositories for EOL releases
+      - name: Fix Debian repositories for Buster (GCC 7-8, Clang 7-9)
         if: matrix.version == 7 || matrix.version == 8 || matrix.version == 9
         run: |
           # Debian Buster reached EOL, repositories moved to archive