diff --git a/src/cmd/cgo/internal/testsanitizers/msan_test.go b/src/cmd/cgo/internal/testsanitizers/msan_test.go
index 83d66f6660d7bf..c534b72442abb1 100644
--- a/src/cmd/cgo/internal/testsanitizers/msan_test.go
+++ b/src/cmd/cgo/internal/testsanitizers/msan_test.go
@@ -71,7 +71,10 @@ func TestMSAN(t *testing.T) {
 			defer dir.RemoveAll(t)
 
 			outPath := dir.Join(name)
-			mustRun(t, config.goCmdWithExperiments("build", []string{"-o", outPath, srcPath(tc.src)}, tc.experiments))
+			buildcmd := config.goCmdWithExperiments("build", []string{"-o", outPath, srcPath(tc.src)}, tc.experiments)
+			// allow tests to define -f flags in CGO_CFLAGS
+			replaceEnv(buildcmd, "CGO_CFLAGS_ALLOW", "-f.*")
+			mustRun(t, buildcmd)
 
 			cmd := hangProneCmd(outPath)
 			if tc.wantErr {
diff --git a/src/cmd/cgo/internal/testsanitizers/testdata/msan8.go b/src/cmd/cgo/internal/testsanitizers/testdata/msan8.go
index 1cb5c5677fa758..e79d343cc7ae4b 100644
--- a/src/cmd/cgo/internal/testsanitizers/testdata/msan8.go
+++ b/src/cmd/cgo/internal/testsanitizers/testdata/msan8.go
@@ -5,6 +5,13 @@
 package main
 
 /*
+// For clang >= 16, uninitialized memory is more aggressively reported.
+// Restore the old behavior for this particular test as it relies on
+// uninitialized variables. See #64616
+#if __clang_major__ >= 16
+#cgo CFLAGS: -fno-sanitize-memory-param-retval
+#endif
+
 #include <pthread.h>
 #include <signal.h>
 #include <stdint.h>