diff --git a/.gitmodules b/.gitmodules
index c2bd4ff9..86209d82 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,6 +1,3 @@
-[submodule "src/ext/zlib"]
-	path = src/ext/zlib
-	url = https://github.com/mitsuba-renderer/zlib.git
 [submodule "src/ext/ptex"]
 	path = src/ext/ptex
 	url = https://github.com/wdas/ptex.git
@@ -36,3 +33,6 @@
 	path = src/ext/glfw
 	url = https://github.com/glfw/glfw.git
 
+[submodule "src/ext/zlib"]
+	path = src/ext/zlib
+	url = https://github.com/madler/zlib.git
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3a6e70c3..91149fec 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -74,7 +74,7 @@ check_ext ("lodepng" "lodepng/examples" 8c6a9e30576f07bf470ad6f09458a2dcd7a6a84a
 check_ext ("qoi" "qoi" 028c75fd26e5e0758c7c711216c00404994c1ad3)
 check_ext ("stb" "stb/tools" af1a5bc352164740c1cc1354942b1c6b72eacb8a)
 check_ext ("utf8proc" "utf8proc/bench" 2484e2ed5e1d9c19edcccf392a7d9920ad90dfaf)
-check_ext ("zlib" "zlib/doc" 54d591eabf9fe0e84c725638f8d5d8d202a093fa)
+check_ext ("zlib" "zlib/doc" 5a82f71ed1dfc0bec044d9702463dbdf84ea3b71)
 add_compile_definitions ("$<$<CONFIG:DEBUG>:PBRT_DEBUG_BUILD>")
 
 enable_testing ()
diff --git a/src/ext/CMakeLists.txt b/src/ext/CMakeLists.txt
index 6436f1ed..2f256853 100644
--- a/src/ext/CMakeLists.txt
+++ b/src/ext/CMakeLists.txt
@@ -82,7 +82,10 @@ add_subdirectory (double-conversion)
 
 set (DOUBLE_CONVERSION_INCLUDE ${CMAKE_CURRENT_SOURCE_DIR}/double-conversion PARENT_SCOPE)
 
-set_property (TARGET double-conversion cctest PROPERTY FOLDER "ext")
+set_property (TARGET double-conversion PROPERTY FOLDER "ext")
+if (TARGET cctest)
+  set_property (TARGET cctest PROPERTY FOLDER "ext")
+endif()
 
 ###########################################################################
 # nanovdb
diff --git a/src/ext/zlib b/src/ext/zlib
index 54d591ea..5a82f71e 160000
--- a/src/ext/zlib
+++ b/src/ext/zlib
@@ -1 +1 @@
-Subproject commit 54d591eabf9fe0e84c725638f8d5d8d202a093fa
+Subproject commit 5a82f71ed1dfc0bec044d9702463dbdf84ea3b71