diff --git a/.github/workflows/test-build.yml b/.github/workflows/test-build.yml
index 33205aa83..566aad3c7 100644
--- a/.github/workflows/test-build.yml
+++ b/.github/workflows/test-build.yml
@@ -93,7 +93,7 @@ jobs:
         shell: bash
         run: |
           rm -rf build
-          cmake -B build . -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_BUILD_TYPE=Release -DYOSYS_COMPILER_LAUNCHER=ccache
+          cmake -B build . -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_BUILD_TYPE=Release -DYOSYS_COMPILER_LAUNCHER=ccache -DYOSYS_USE_BUNDLED_LIBS=ON
           cmake --build build -j$procs
           ctest --test-dir build/tests/unit
 
diff --git a/CMakeLists.txt b/CMakeLists.txt
index bb3766fd7..3745ea0fe 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -57,6 +57,8 @@ option(YOSYS_WITHOUT_SLANG "Disable Slang integration" OFF)
 option(YOSYS_WITHOUT_TCL "Disable Tcl integration" OFF)
 option(YOSYS_WITH_PYTHON "Enable Python integration" OFF)
 
+option(YOSYS_USE_BUNDLED_LIBS "Use bundled third-party libraries" OFF)
+
 set(YOSYS_VERIFIC_DIR "" CACHE FILEPATH "Path to the Verific source code (empty to disable)")
 set(YOSYS_VERIFIC_COMPONENTS "" CACHE STRING
 	"List of Verific components to link (empty for autodetect)")
diff --git a/frontends/CMakeLists.txt b/frontends/CMakeLists.txt
index 6e6eda488..983fa2fd9 100644
--- a/frontends/CMakeLists.txt
+++ b/frontends/CMakeLists.txt
@@ -6,6 +6,8 @@ add_subdirectory(json)
 add_subdirectory(liberty)
 add_subdirectory(rpc)
 add_subdirectory(rtlil)
-add_subdirectory(slang)
+if (NOT YOSYS_WITHOUT_SLANG)
+    add_subdirectory(slang)
+endif()
 add_subdirectory(verific)
 add_subdirectory(verilog)
diff --git a/frontends/slang/CMakeLists.txt b/frontends/slang/CMakeLists.txt
index dae714de9..83bf98573 100644
--- a/frontends/slang/CMakeLists.txt
+++ b/frontends/slang/CMakeLists.txt
@@ -35,5 +35,4 @@ yosys_frontend(slang
 		${CMAKE_CURRENT_BINARY_DIR}
 	LIBRARIES
 		$<${YOSYS_ENABLE_SLANG}:slang::slang>
-		fmt::fmt
 )
diff --git a/libs/CMakeLists.txt b/libs/CMakeLists.txt
index 5ea08ef9d..cb81b3af2 100644
--- a/libs/CMakeLists.txt
+++ b/libs/CMakeLists.txt
@@ -12,28 +12,49 @@ block()
     include(FetchContent)
     set(FETCHCONTENT_FULLY_DISCONNECTED ON)
 
-    option(FMT_INSTALL OFF)
-    FetchContent_Declare(
-        fmt
-        EXCLUDE_FROM_ALL
-        SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/fmt
-    )
-    FetchContent_MakeAvailable(fmt)
+    if(NOT YOSYS_USE_BUNDLED_LIBS)
+        find_package(fmt 12.2 QUIET)
+    endif()
+    if(fmt_FOUND)
+        set(SLANG_USE_SYSTEM_FMT ON)
+    else()
+        option(FMT_INSTALL OFF)
+        FetchContent_Declare(
+            fmt
+            EXCLUDE_FROM_ALL
+            SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/fmt
+        )
+        FetchContent_MakeAvailable(fmt)
+    endif()
 
-    FetchContent_Declare(
-        tomlplusplus
-        EXCLUDE_FROM_ALL
-        SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/tomlplusplus
-    )
-    FetchContent_MakeAvailable(tomlplusplus)
+    if(NOT YOSYS_USE_BUNDLED_LIBS)
+        find_package(tomlplusplus 3.4 QUIET)
+    endif()
+    if(tomlplusplus_FOUND)
+        set(SLANG_USE_SYSTEM_TOMLPLUSPLUS ON)
+    else()
+        FetchContent_Declare(
+            tomlplusplus
+            EXCLUDE_FROM_ALL
+            SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/tomlplusplus
+        )
+        FetchContent_MakeAvailable(tomlplusplus)
+    endif()
 
-    FetchContent_Declare(
-        boost_regex
-        EXCLUDE_FROM_ALL
-        SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/boost_regex
-        SOURCE_SUBDIR _no_build_
-    )
-    FetchContent_MakeAvailable(boost_regex)
+    if(NOT YOSYS_USE_BUNDLED_LIBS)
+        find_package(Boost 1.87.0 CONFIG QUIET)
+    endif()
+    if(Boost_FOUND)
+        set(SLANG_USE_SYSTEM_BOOST ON)
+    else()
+        FetchContent_Declare(
+            boost_regex
+            EXCLUDE_FROM_ALL
+            SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/boost_regex
+            SOURCE_SUBDIR _no_build_
+        )
+        FetchContent_MakeAvailable(boost_regex)
+    endif()
 
     if (NOT YOSYS_WITHOUT_SLANG)
         set(SLANG_USE_MIMALLOC OFF)
diff --git a/libs/slang b/libs/slang
index 617575096..8acc660a2 160000
--- a/libs/slang
+++ b/libs/slang
@@ -1 +1 @@
-Subproject commit 6175750969f17289695f94be5105f6006c82eb61
+Subproject commit 8acc660a20b70de48ecec1c7471863e6f4b3ae6f