diff --git a/builder/images/base-linux64/ct-ng-config b/builder/images/base-linux64/ct-ng-config
index 3a627153b6..8b97b52b17 100644
--- a/builder/images/base-linux64/ct-ng-config
+++ b/builder/images/base-linux64/ct-ng-config
@@ -825,7 +825,7 @@ CT_ISL_V_0_26=y
 # CT_ISL_V_0_16 is not set
 # CT_ISL_V_0_15 is not set
 CT_ISL_VERSION="0.26"
-CT_ISL_MIRRORS="https://libisl.sourceforge.io"
+CT_ISL_MIRRORS="https://github.com/gnattu/isl/releases/download/isl-0.26"
 CT_ISL_ARCHIVE_FILENAME="@{pkg_name}-@{version}"
 CT_ISL_ARCHIVE_DIRNAME="@{pkg_name}-@{version}"
 CT_ISL_ARCHIVE_FORMATS=".tar.xz .tar.bz2 .tar.gz"
diff --git a/builder/images/base-linuxarm64/ct-ng-config b/builder/images/base-linuxarm64/ct-ng-config
index 57871f6238..f48653b168 100644
--- a/builder/images/base-linuxarm64/ct-ng-config
+++ b/builder/images/base-linuxarm64/ct-ng-config
@@ -829,7 +829,7 @@ CT_ISL_V_0_26=y
 # CT_ISL_V_0_16 is not set
 # CT_ISL_V_0_15 is not set
 CT_ISL_VERSION="0.26"
-CT_ISL_MIRRORS="https://libisl.sourceforge.io"
+CT_ISL_MIRRORS="https://github.com/gnattu/isl/releases/download/isl-0.26"
 CT_ISL_ARCHIVE_FILENAME="@{pkg_name}-@{version}"
 CT_ISL_ARCHIVE_DIRNAME="@{pkg_name}-@{version}"
 CT_ISL_ARCHIVE_FORMATS=".tar.xz .tar.bz2 .tar.gz"
diff --git a/builder/images/base-win64/ct-ng-config b/builder/images/base-win64/ct-ng-config
index f92fe4fc3e..f14ce9e6c7 100644
--- a/builder/images/base-win64/ct-ng-config
+++ b/builder/images/base-win64/ct-ng-config
@@ -663,7 +663,7 @@ CT_ISL_V_0_26=y
 # CT_ISL_V_0_16 is not set
 # CT_ISL_V_0_15 is not set
 CT_ISL_VERSION="0.26"
-CT_ISL_MIRRORS="https://libisl.sourceforge.io"
+CT_ISL_MIRRORS="https://github.com/gnattu/isl/releases/download/isl-0.26"
 CT_ISL_ARCHIVE_FILENAME="@{pkg_name}-@{version}"
 CT_ISL_ARCHIVE_DIRNAME="@{pkg_name}-@{version}"
 CT_ISL_ARCHIVE_FORMATS=".tar.xz .tar.bz2 .tar.gz"