diff --git a/netwerk/cache2/CacheEntry.cpp b/netwerk/cache2/CacheEntry.cpp
index db6daee1d538..43a573910246 100644
--- a/netwerk/cache2/CacheEntry.cpp
+++ b/netwerk/cache2/CacheEntry.cpp
@@ -191,6 +191,13 @@ NS_IMPL_ISUPPORTS(CacheEntry,
                   nsIRunnable,
                   CacheFileListener)
 
+/* static */
+uint64_t CacheEntry::GetNextId()
+{
+  static Atomic<uint64_t, Relaxed> id(0);
+  return ++id;
+}
+
 CacheEntry::CacheEntry(const nsACString& aStorageID,
                        const nsACString& aURI,
                        const nsACString& aEnhanceID,
@@ -217,6 +224,7 @@ CacheEntry::CacheEntry(const nsACString& aStorageID,
 , mWriter(nullptr)
 , mPredictedDataSize(0)
 , mUseCount(0)
+, mCacheEntryId(GetNextId())
 {
   LOG(("CacheEntry::CacheEntry [this=%p]", this));
 
@@ -1048,6 +1056,12 @@ NS_IMETHODIMP CacheEntry::GetKey(nsACString & aKey)
   return NS_OK;
 }
 
+NS_IMETHODIMP CacheEntry::GetCacheEntryId(uint64_t *aCacheEntryId)
+{
+  *aCacheEntryId = mCacheEntryId;
+  return NS_OK;
+}
+
 NS_IMETHODIMP CacheEntry::GetFetchCount(int32_t *aFetchCount)
 {
   NS_ENSURE_SUCCESS(mFileStatus, NS_ERROR_NOT_AVAILABLE);
diff --git a/netwerk/cache2/CacheEntry.h b/netwerk/cache2/CacheEntry.h
index a13030aa0ea8..dbd8275bf808 100644
--- a/netwerk/cache2/CacheEntry.h
+++ b/netwerk/cache2/CacheEntry.h
@@ -54,6 +54,8 @@ public:
   NS_DECL_NSICACHEENTRY
   NS_DECL_NSIRUNNABLE
 
+  static uint64_t GetNextId();
+
   CacheEntry(const nsACString& aStorageID, const nsACString& aURI, const nsACString& aEnhanceID,
              bool aUseDisk, bool aSkipSizeCheck, bool aPin);
 
@@ -383,6 +385,8 @@ private:
   int64_t mPredictedDataSize;
   mozilla::TimeStamp mLoadStart;
   uint32_t mUseCount;
+
+  const uint64_t mCacheEntryId;
 };
 
 
diff --git a/netwerk/cache2/OldWrappers.cpp b/netwerk/cache2/OldWrappers.cpp
index 66d16a8935c4..698c7af6526b 100644
--- a/netwerk/cache2/OldWrappers.cpp
+++ b/netwerk/cache2/OldWrappers.cpp
@@ -346,13 +346,13 @@ _OldGetDiskConsumption::VisitEntry(const char * deviceID,
 // _OldCacheEntryWrapper
 
 _OldCacheEntryWrapper::_OldCacheEntryWrapper(nsICacheEntryDescriptor* desc)
-: mOldDesc(desc), mOldInfo(desc)
+: mOldDesc(desc), mOldInfo(desc), mCacheEntryId(CacheEntry::GetNextId())
 {
   LOG(("Creating _OldCacheEntryWrapper %p for descriptor %p", this, desc));
 }
 
 _OldCacheEntryWrapper::_OldCacheEntryWrapper(nsICacheEntryInfo* info)
-: mOldDesc(nullptr), mOldInfo(info)
+: mOldDesc(nullptr), mOldInfo(info), mCacheEntryId(CacheEntry::GetNextId())
 {
   LOG(("Creating _OldCacheEntryWrapper %p for info %p", this, info));
 }
diff --git a/netwerk/cache2/OldWrappers.h b/netwerk/cache2/OldWrappers.h
index 651633e6017f..56433278d119 100644
--- a/netwerk/cache2/OldWrappers.h
+++ b/netwerk/cache2/OldWrappers.h
@@ -115,6 +115,11 @@ public:
   {
     return mOldInfo->GetKey(aKey);
   }
+  NS_IMETHOD GetCacheEntryId(uint64_t *aCacheEntryId) override
+  {
+    *aCacheEntryId = mCacheEntryId;
+    return NS_OK;
+  }
   NS_IMETHOD GetFetchCount(int32_t *aFetchCount) override
   {
     return mOldInfo->GetFetchCount(aFetchCount);
@@ -176,6 +181,8 @@ private:
   _OldCacheEntryWrapper() = delete;
   nsICacheEntryDescriptor* mOldDesc; // ref holded in mOldInfo
   nsCOMPtr<nsICacheEntryInfo> mOldInfo;
+
+  const uint64_t mCacheEntryId;
 };
 
 
diff --git a/netwerk/cache2/nsICacheEntry.idl b/netwerk/cache2/nsICacheEntry.idl
index e2322279ecbc..38e41d056f84 100644
--- a/netwerk/cache2/nsICacheEntry.idl
+++ b/netwerk/cache2/nsICacheEntry.idl
@@ -27,6 +27,12 @@ interface nsICacheEntry : nsISupports
    */
   readonly attribute ACString key;
 
+  /**
+   * The unique ID for every nsICacheEntry instance, which can be used to check
+   * whether two pieces of information are from the same nsICacheEntry instance.
+   */
+  readonly attribute uint64_t cacheEntryId;
+
   /**
    * Whether the entry is memory/only or persisted to disk.
    * Note: private browsing entries are reported as persistent for consistency