diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 67c856a..7c342b2 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -239,7 +239,10 @@ if(MSVC)
         /sdl
         /guard:cf
         /GS
-        /DYNAMICBASE)
+        /DYNAMICBASE
+        # c2pa_cpp wraps the deprecated C API surface, silence C4996 so the
+        # wrapper still builds cleanly while end users still see the warning.
+        /wd4996)
 
     target_link_options(c2pa_cpp PRIVATE
         /DYNAMICBASE
@@ -254,6 +257,10 @@ else()
         -Wstack-protector
         -fstack-protector-strong
         -fPIC
+        # c2pa_cpp wraps the deprecated C API surface, silence the warning
+        # here so the wrapper still builds with -Werror while end users still
+        # see the deprecation warning.
+        -Wno-deprecated-declarations
     )
 
     if(APPLE)
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 8fc031d..217c94d 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -182,6 +182,10 @@ if(WIN32)
 else()
     # On Unix systems, link directly to the shared library
     target_link_libraries(ctest PRIVATE "${C2PA_C_LIB}")
+    # c-app-test deliberately exercises the deprecated C API so we can keep
+    # testing it. Silences the resulting -Wdeprecated-declarations so -Werror
+    # does not fail the (test) build.
+    target_compile_options(ctest PRIVATE -Wno-deprecated-declarations)
 endif()
 target_include_directories(ctest PRIVATE
     "${C2PA_PREBUILT_INCLUDE_DIR}"