diff --git a/src/node.cc b/src/node.cc
index c7e20acfaf9aca..a9b909b74e0e6b 100644
--- a/src/node.cc
+++ b/src/node.cc
@@ -741,6 +741,11 @@ static ExitCode InitializeNodeWithArgsInternal(
   // used in diagnostic reports.
   per_process::cli_options->cmdline = *argv;
 
+  // Node provides a "v8.setFlagsFromString" method to dynamically change flags.
+  // Hence do not freeze flags when initializing V8. In a browser setting, this
+  // is security relevant, for Node it's less important.
+  V8::SetFlagsFromString("--no-freeze-flags-after-init");
+
 #if defined(NODE_V8_OPTIONS)
   // Should come before the call to V8::SetFlagsFromCommandLine()
   // so the user can disable a flag --foo at run-time by passing
diff --git a/test/cctest/node_test_fixture.cc b/test/cctest/node_test_fixture.cc
index 5cbbee8f1ece2c..59cf7eee49e530 100644
--- a/test/cctest/node_test_fixture.cc
+++ b/test/cctest/node_test_fixture.cc
@@ -24,6 +24,11 @@ void NodeTestEnvironment::SetUp() {
 #endif
   cppgc::InitializeProcess(
       NodeZeroIsolateTestFixture::platform->GetPageAllocator());
+
+  // Before initializing V8, disable the --freeze-flags-after-init flag, so
+  // individual tests can set their own flags.
+  v8::V8::SetFlagsFromString("--no-freeze-flags-after-init");
+
   v8::V8::Initialize();
 }