diff --git a/dom/html/HTMLInputElement.cpp b/dom/html/HTMLInputElement.cpp
index 5761b12e68..374fb14ef1 100644
--- a/dom/html/HTMLInputElement.cpp
+++ b/dom/html/HTMLInputElement.cpp
@@ -1255,14 +1255,6 @@ HTMLInputElement::BeforeSetAttr(int32_t aNameSpaceID, nsIAtom* aName,
         mType == NS_FORM_INPUT_RADIO &&
         (mForm || mDoneCreating)) {
       WillRemoveFromRadioGroup();
-    } else if (aNotify && aName == nsGkAtoms::src &&
-               mType == NS_FORM_INPUT_IMAGE) {
-      if (aValue) {
-        LoadImage(aValue->String(), true, aNotify, eImageLoadType_Normal);
-      } else {
-        // Null value means the attr got unset; drop the image
-        CancelImageRequests(aNotify);
-      }
     } else if (aNotify && aName == nsGkAtoms::disabled) {
       mDisabledChanged = true;
     } else if (mType == NS_FORM_INPUT_RADIO && aName == nsGkAtoms::required) {
@@ -1303,6 +1295,21 @@ HTMLInputElement::AfterSetAttr(int32_t aNameSpaceID, nsIAtom* aName,
       UpdateValueMissingValidityStateForRadio(false);
     }
 
+    if (aName == nsGkAtoms::src) {
+      mSrcTriggeringPrincipal = nsContentUtils::GetAttrTriggeringPrincipal(
+          this, aValue ? aValue->GetStringValue() : EmptyString(),
+          aSubjectPrincipal);
+      if (aNotify && mType == NS_FORM_INPUT_IMAGE) {
+        if (aValue) {
+          LoadImage(aValue->GetStringValue(), true, aNotify, eImageLoadType_Normal,
+                    mSrcTriggeringPrincipal);
+        } else {
+          // Null value means the attr got unset; drop the image
+          CancelImageRequests(aNotify);
+        }
+      }
+    }
+
     // If @value is changed and BF_VALUE_CHANGED is false, @value is the value
     // of the element so, if the value of the element is different than @value,
     // we have to re-set it. This is only the case when GetValueMode() returns
@@ -4961,7 +4968,7 @@ HTMLInputElement::MaybeLoadImage()
   nsAutoString uri;
   if (mType == NS_FORM_INPUT_IMAGE &&
       GetAttr(kNameSpaceID_None, nsGkAtoms::src, uri) &&
-      (NS_FAILED(LoadImage(uri, false, true, eImageLoadType_Normal)) ||
+      (NS_FAILED(LoadImage(uri, false, true, eImageLoadType_Normal, mSrcTriggeringPrincipal)) ||
        !LoadingEnabled())) {
     CancelImageRequests(true);
   }
@@ -5165,7 +5172,7 @@ HTMLInputElement::HandleTypeChange(uint8_t aNewType, bool aNotify)
     // whether we have an image to load;
     nsAutoString src;
     if (GetAttr(kNameSpaceID_None, nsGkAtoms::src, src)) {
-      LoadImage(src, false, aNotify, eImageLoadType_Normal);
+      LoadImage(src, false, aNotify, eImageLoadType_Normal, mSrcTriggeringPrincipal);
     }
   }
 
diff --git a/dom/html/HTMLInputElement.h b/dom/html/HTMLInputElement.h
index 45464f638b..e46be30ea7 100644
--- a/dom/html/HTMLInputElement.h
+++ b/dom/html/HTMLInputElement.h
@@ -638,10 +638,13 @@ public:
     SetUnsignedIntAttr(nsGkAtoms::size, aValue, DEFAULT_COLS, aRv);
   }
 
-  // XPCOM GetSrc() is OK
-  void SetSrc(const nsAString& aValue, ErrorResult& aRv)
+  void GetSrc(nsAString& aValue, nsIPrincipal&)
   {
-    SetHTMLAttr(nsGkAtoms::src, aValue, aRv);
+    GetURIAttr(nsGkAtoms::src, nullptr, aValue);
+  }
+  void SetSrc(const nsAString& aValue, nsIPrincipal& aTriggeringPrincipal, ErrorResult& aRv)
+  {
+    SetHTMLAttr(nsGkAtoms::src, aValue, aTriggeringPrincipal, aRv);
   }
 
   // XPCOM GetStep() is OK
@@ -1559,6 +1562,11 @@ protected:
    */
   nsTextEditorState::SelectionProperties mSelectionProperties;
 
+  /**
+   * The triggering principal for the src attribute.
+   */
+  nsCOMPtr<nsIPrincipal> mSrcTriggeringPrincipal;
+
   // Step scale factor values, for input types that have one.
   static const Decimal kStepScaleFactorDate;
   static const Decimal kStepScaleFactorNumberRange;
diff --git a/dom/webidl/HTMLInputElement.webidl b/dom/webidl/HTMLInputElement.webidl
index 528689bbd1..1eefaea61e 100644
--- a/dom/webidl/HTMLInputElement.webidl
+++ b/dom/webidl/HTMLInputElement.webidl
@@ -81,7 +81,7 @@ interface HTMLInputElement : HTMLElement {
            attribute boolean required;
   [CEReactions, Pure, SetterThrows]
            attribute unsigned long size;
-  [CEReactions, Pure, SetterThrows]
+  [CEReactions, Pure, NeedsSubjectPrincipal, SetterThrows]
            attribute DOMString src;
   [CEReactions, Pure, SetterThrows]
            attribute DOMString step;