diff --git a/mozglue/misc/WindowsProcessMitigations.cpp b/mozglue/misc/WindowsProcessMitigations.cpp
index bd5a72b5f0a5..391876cef4c8 100644
--- a/mozglue/misc/WindowsProcessMitigations.cpp
+++ b/mozglue/misc/WindowsProcessMitigations.cpp
@@ -17,11 +17,18 @@ BOOL WINAPI GetProcessMitigationPolicy(
 
 namespace mozilla {
 
-MFBT_API bool IsWin32kLockedDown() {
+static const DynamicallyLinkedFunctionPtr<
+    decltype(&::GetProcessMitigationPolicy)>&
+FetchGetProcessMitigationPolicyFunc() {
   static const DynamicallyLinkedFunctionPtr<decltype(
       &::GetProcessMitigationPolicy)>
       pGetProcessMitigationPolicy(L"kernel32.dll",
                                   "GetProcessMitigationPolicy");
+  return pGetProcessMitigationPolicy;
+}
+
+MFBT_API bool IsWin32kLockedDown() {
+  auto& pGetProcessMitigationPolicy = FetchGetProcessMitigationPolicyFunc();
   if (!pGetProcessMitigationPolicy) {
     return false;
   }
@@ -36,4 +43,20 @@ MFBT_API bool IsWin32kLockedDown() {
   return polInfo.DisallowWin32kSystemCalls;
 }
 
+MFBT_API bool IsDynamicCodeDisabled() {
+  auto& pGetProcessMitigationPolicy = FetchGetProcessMitigationPolicyFunc();
+  if (!pGetProcessMitigationPolicy) {
+    return false;
+  }
+
+  PROCESS_MITIGATION_DYNAMIC_CODE_POLICY polInfo;
+  if (!pGetProcessMitigationPolicy(::GetCurrentProcess(),
+                                   ProcessDynamicCodePolicy, &polInfo,
+                                   sizeof(polInfo))) {
+    return false;
+  }
+
+  return polInfo.ProhibitDynamicCode;
+}
+
 }  // namespace mozilla
diff --git a/mozglue/misc/WindowsProcessMitigations.h b/mozglue/misc/WindowsProcessMitigations.h
index 353aa5b734d3..b8721080ea4b 100644
--- a/mozglue/misc/WindowsProcessMitigations.h
+++ b/mozglue/misc/WindowsProcessMitigations.h
@@ -12,6 +12,7 @@
 namespace mozilla {
 
 MFBT_API bool IsWin32kLockedDown();
+MFBT_API bool IsDynamicCodeDisabled();
 
 }  // namespace mozilla
 
diff --git a/mozglue/misc/interceptor/Trampoline.h b/mozglue/misc/interceptor/Trampoline.h
index b9d9a61ac059..909de6e11564 100644
--- a/mozglue/misc/interceptor/Trampoline.h
+++ b/mozglue/misc/interceptor/Trampoline.h
@@ -12,6 +12,7 @@
 #include "mozilla/CheckedInt.h"
 #include "mozilla/Maybe.h"
 #include "mozilla/Types.h"
+#include "mozilla/WindowsProcessMitigations.h"
 
 namespace mozilla {
 namespace interceptor {
@@ -345,9 +346,18 @@ class MOZ_STACK_CLASS TrampolineCollection final {
       return;
     }
 
-    DebugOnly<BOOL> ok = mMMPolicy.Protect(aLocalBase, aNumTramps * aTrampSize,
-                                           PAGE_EXECUTE_READWRITE, &mPrevProt);
-    MOZ_ASSERT(ok);
+    BOOL ok = mMMPolicy.Protect(aLocalBase, aNumTramps * aTrampSize,
+                                PAGE_EXECUTE_READWRITE, &mPrevProt);
+    if (!ok) {
+      // When destroying a sandboxed process that uses
+      // MITIGATION_DYNAMIC_CODE_DISABLE, we won't be allowed to write to our
+      // executable memory so we just do nothing.  If we fail to get access
+      // to memory for any other reason, we still don't want to crash but we
+      // do assert.
+      MOZ_ASSERT(IsDynamicCodeDisabled());
+      mNumTramps = 0;
+      mPrevProt = 0;
+    }
   }
 
   ~TrampolineCollection() {
@@ -405,7 +415,7 @@ class MOZ_STACK_CLASS TrampolineCollection final {
   uint8_t* const mLocalBase;
   const uintptr_t mRemoteBase;
   const uint32_t mTrampSize;
-  const uint32_t mNumTramps;
+  uint32_t mNumTramps;
   uint32_t mPrevProt;
   CRITICAL_SECTION* mCS;