diff --git a/dom/base/ResponsiveImageSelector.cpp b/dom/base/ResponsiveImageSelector.cpp
index 43a5138faa45..5ebb5b202006 100644
--- a/dom/base/ResponsiveImageSelector.cpp
+++ b/dom/base/ResponsiveImageSelector.cpp
@@ -116,7 +116,8 @@ ResponsiveImageSelector::~ResponsiveImageSelector()
 
 // http://www.whatwg.org/specs/web-apps/current-work/#processing-the-image-candidates
 bool
-ResponsiveImageSelector::SetCandidatesFromSourceSet(const nsAString & aSrcSet)
+ResponsiveImageSelector::SetCandidatesFromSourceSet(const nsAString & aSrcSet,
+                                                    nsIPrincipal* aTriggeringPrincipal)
 {
   ClearSelectedCandidate();
 
@@ -168,6 +169,8 @@ ResponsiveImageSelector::SetCandidatesFromSourceSet(const nsAString & aSrcSet)
     ResponsiveImageCandidate candidate;
     if (candidate.ConsumeDescriptors(iter, end)) {
       candidate.SetURLSpec(urlStr);
+      candidate.SetTriggeringPrincipal(nsContentUtils::GetAttrTriggeringPrincipal(
+          Content(), urlStr, aTriggeringPrincipal));
       AppendCandidateIfUnique(candidate);
     }
   }
@@ -208,7 +211,8 @@ ResponsiveImageSelector::Document()
 }
 
 void
-ResponsiveImageSelector::SetDefaultSource(const nsAString& aURLString)
+ResponsiveImageSelector::SetDefaultSource(const nsAString& aURLString,
+                                          nsIPrincipal* aPrincipal)
 {
   ClearSelectedCandidate();
 
@@ -220,6 +224,7 @@ ResponsiveImageSelector::SetDefaultSource(const nsAString& aURLString)
   }
 
   mDefaultSourceURL = aURLString;
+  mDefaultSourceTriggeringPrincipal = aPrincipal;
 
   // Add new default to end of list
   MaybeAppendDefaultCandidate();
@@ -292,6 +297,7 @@ ResponsiveImageSelector::MaybeAppendDefaultCandidate()
   ResponsiveImageCandidate defaultCandidate;
   defaultCandidate.SetParameterDefault();
   defaultCandidate.SetURLSpec(mDefaultSourceURL);
+  defaultCandidate.SetTriggeringPrincipal(mDefaultSourceTriggeringPrincipal);
   // We don't use MaybeAppend since we want to keep this even if it can never
   // match, as it may if the source set changes.
   mCandidates.AppendElement(defaultCandidate);
@@ -330,6 +336,17 @@ ResponsiveImageSelector::GetSelectedImageDensity()
   return mCandidates[bestIndex].Density(this);
 }
 
+nsIPrincipal*
+ResponsiveImageSelector::GetSelectedImageTriggeringPrincipal()
+{
+  int bestIndex = GetSelectedCandidateIndex();
+  if (bestIndex < 0) {
+    return nullptr;
+  }
+
+  return mCandidates[bestIndex].TriggeringPrincipal();
+}
+
 bool
 ResponsiveImageSelector::SelectImage(bool aReselect)
 {
@@ -458,8 +475,10 @@ ResponsiveImageCandidate::ResponsiveImageCandidate()
 }
 
 ResponsiveImageCandidate::ResponsiveImageCandidate(const nsAString& aURLString,
-                                                   double aDensity)
+                                                   double aDensity,
+                                                   nsIPrincipal* aTriggeringPrincipal)
   : mURLString(aURLString)
+  , mTriggeringPrincipal(aTriggeringPrincipal)
 {
   mType = eCandidateType_Density;
   mValue.mDensity = aDensity;
@@ -472,6 +491,12 @@ ResponsiveImageCandidate::SetURLSpec(const nsAString& aURLString)
   mURLString = aURLString;
 }
 
+void
+ResponsiveImageCandidate::SetTriggeringPrincipal(nsIPrincipal* aPrincipal)
+{
+  mTriggeringPrincipal = aPrincipal;
+}
+
 void
 ResponsiveImageCandidate::SetParameterAsComputedWidth(int32_t aWidth)
 {
@@ -718,6 +743,12 @@ ResponsiveImageCandidate::URLString() const
   return mURLString;
 }
 
+nsIPrincipal*
+ResponsiveImageCandidate::TriggeringPrincipal() const
+{
+  return mTriggeringPrincipal;
+}
+
 double
 ResponsiveImageCandidate::Density(ResponsiveImageSelector *aSelector) const
 {
diff --git a/dom/base/ResponsiveImageSelector.h b/dom/base/ResponsiveImageSelector.h
index c722e8784c72..210338babeac 100644
--- a/dom/base/ResponsiveImageSelector.h
+++ b/dom/base/ResponsiveImageSelector.h
@@ -45,14 +45,16 @@ public:
 
   // Given a srcset string, parse and replace current candidates (does not
   // replace default source)
-  bool SetCandidatesFromSourceSet(const nsAString & aSrcSet);
+  bool SetCandidatesFromSourceSet(const nsAString & aSrcSet,
+                                  nsIPrincipal* aTriggeringPrincipal = nullptr);
 
   // Fill the source sizes from a valid sizes descriptor. Returns false if
   // descriptor is invalid.
   bool SetSizesFromDescriptor(const nsAString & aSizesDescriptor);
 
   // Set the default source, treated as the least-precedence 1.0 density source.
-  void SetDefaultSource(const nsAString& aURLString);
+  void SetDefaultSource(const nsAString& aURLString,
+                        nsIPrincipal* aPrincipal = nullptr);
 
   uint32_t NumCandidates(bool aIncludeDefault = true);
 
@@ -70,6 +72,7 @@ public:
   // Returns false if there is no selected image
   bool GetSelectedImageURLSpec(nsAString& aResult);
   double GetSelectedImageDensity();
+  nsIPrincipal* GetSelectedImageTriggeringPrincipal();
 
   // Runs image selection now if necessary. If an image has already
   // been choosen, takes no action unless aReselect is true.
@@ -108,6 +111,7 @@ private:
   nsCOMPtr<nsINode> mOwnerNode;
   // The cached URL for default candidate.
   nsString mDefaultSourceURL;
+  nsCOMPtr<nsIPrincipal> mDefaultSourceTriggeringPrincipal;
   // If this array contains an eCandidateType_Default, it should be the last
   // element, such that the Setters can preserve/replace it respectively.
   nsTArray<ResponsiveImageCandidate> mCandidates;
@@ -123,9 +127,11 @@ private:
 class ResponsiveImageCandidate {
 public:
   ResponsiveImageCandidate();
-  ResponsiveImageCandidate(const nsAString& aURLString, double aDensity);
+  ResponsiveImageCandidate(const nsAString& aURLString, double aDensity,
+                           nsIPrincipal* aTriggeringPrincipal = nullptr);
 
   void SetURLSpec(const nsAString& aURLString);
+  void SetTriggeringPrincipal(nsIPrincipal* aPrincipal);
   // Set this as a default-candidate. This behaves the same as density 1.0, but
   // has a differing type such that it can be replaced by subsequent
   // SetDefaultSource calls.
@@ -148,6 +154,7 @@ public:
   bool HasSameParameter(const ResponsiveImageCandidate & aOther) const;
 
   const nsAString& URLString() const;
+  nsIPrincipal* TriggeringPrincipal() const;
 
   // Compute and return the density relative to a selector.
   double Density(ResponsiveImageSelector *aSelector) const;
@@ -172,6 +179,7 @@ public:
 private:
 
   nsString mURLString;
+  nsCOMPtr<nsIPrincipal> mTriggeringPrincipal;
   eCandidateType mType;
   union {
     double mDensity;
diff --git a/dom/html/HTMLImageElement.cpp b/dom/html/HTMLImageElement.cpp
index 1ee0dee139f8..1a09458f150e 100644
--- a/dom/html/HTMLImageElement.cpp
+++ b/dom/html/HTMLImageElement.cpp
@@ -368,6 +368,8 @@ HTMLImageElement::AfterSetAttr(int32_t aNameSpaceID, nsAtom* aName,
     // initaiated by a user interaction.
     mUseUrgentStartForChannel = EventStateManager::IsHandlingUserInput();
 
+    mSrcsetTriggeringPrincipal = aMaybeScriptedPrincipal;
+
     PictureSourceSrcsetChanged(this, attrVal.String(), aNotify);
   } else if (aName == nsGkAtoms::sizes &&
              aNameSpaceID == kNameSpaceID_None) {
@@ -426,7 +428,8 @@ HTMLImageElement::AfterMaybeChangeAttr(int32_t aNamespaceID, nsAtom* aName,
     if (InResponsiveMode()) {
       if (mResponsiveSelector &&
           mResponsiveSelector->Content() == this) {
-        mResponsiveSelector->SetDefaultSource(aValue.String());
+        mResponsiveSelector->SetDefaultSource(aValue.String(),
+                                              mSrcTriggeringPrincipal);
       }
       QueueImageLoadTask(true);
     } else if (aNotify && OwnerDoc()->IsCurrentActiveDocument()) {
@@ -981,13 +984,15 @@ HTMLImageElement::LoadSelectedImage(bool aForce, bool aNotify, bool aAlwaysLoad)
   double currentDensity = 1.0; // default to 1.0 for the src attribute case
   if (mResponsiveSelector) {
     nsCOMPtr<nsIURI> url = mResponsiveSelector->GetSelectedImageURL();
+    nsCOMPtr<nsIPrincipal> triggeringPrincipal = mResponsiveSelector->GetSelectedImageTriggeringPrincipal();
     selectedSource = url;
     currentDensity = mResponsiveSelector->GetSelectedImageDensity();
     if (!aAlwaysLoad && SelectedSourceMatchesLast(selectedSource, currentDensity)) {
       return NS_OK;
     }
     if (url) {
-      rv = LoadImage(url, aForce, aNotify, eImageLoadType_Imageset);
+      rv = LoadImage(url, aForce, aNotify, eImageLoadType_Imageset,
+                     triggeringPrincipal);
     }
   } else {
     nsAutoString src;
@@ -1036,7 +1041,11 @@ HTMLImageElement::PictureSourceSrcsetChanged(nsIContent *aSourceNode,
   if (aSourceNode == currentSrc) {
     // We're currently using this node as our responsive selector
     // source.
-    mResponsiveSelector->SetCandidatesFromSourceSet(aNewValue);
+    nsCOMPtr<nsIPrincipal> principal;
+    if (aSourceNode == this) {
+      principal = mSrcsetTriggeringPrincipal;
+    }
+    mResponsiveSelector->SetCandidatesFromSourceSet(aNewValue, principal);
   }
 
   if (!mInDocResponsiveContent && IsInComposedDoc()) {
@@ -1221,6 +1230,8 @@ HTMLImageElement::SourceElementMatches(nsIContent* aSourceNode)
 bool
 HTMLImageElement::TryCreateResponsiveSelector(nsIContent *aSourceNode)
 {
+  nsCOMPtr<nsIPrincipal> principal;
+
   // Skip if this is not a <source> with matching media query
   bool isSourceTag = aSourceNode->IsHTMLElement(nsGkAtoms::source);
   if (isSourceTag) {
@@ -1230,6 +1241,7 @@ HTMLImageElement::TryCreateResponsiveSelector(nsIContent *aSourceNode)
   } else if (aSourceNode->IsHTMLElement(nsGkAtoms::img)) {
     // Otherwise this is the <img> tag itself
     MOZ_ASSERT(aSourceNode == this);
+    principal = mSrcsetTriggeringPrincipal;
   }
 
   // Skip if has no srcset or an empty srcset
@@ -1245,7 +1257,7 @@ HTMLImageElement::TryCreateResponsiveSelector(nsIContent *aSourceNode)
 
   // Try to parse
   RefPtr<ResponsiveImageSelector> sel = new ResponsiveImageSelector(aSourceNode);
-  if (!sel->SetCandidatesFromSourceSet(srcset)) {
+  if (!sel->SetCandidatesFromSourceSet(srcset, principal)) {
     // No possible candidates, don't need to bother parsing sizes
     return false;
   }
@@ -1259,7 +1271,7 @@ HTMLImageElement::TryCreateResponsiveSelector(nsIContent *aSourceNode)
     MOZ_ASSERT(aSourceNode == this);
     nsAutoString src;
     if (GetAttr(kNameSpaceID_None, nsGkAtoms::src, src) && !src.IsEmpty()) {
-      sel->SetDefaultSource(src);
+      sel->SetDefaultSource(src, mSrcTriggeringPrincipal);
     }
   }
 
diff --git a/dom/html/HTMLImageElement.h b/dom/html/HTMLImageElement.h
index 8917be7bb9e3..952cb7bfb02a 100644
--- a/dom/html/HTMLImageElement.h
+++ b/dom/html/HTMLImageElement.h
@@ -150,13 +150,13 @@ public:
   {
     SetHTMLAttr(nsGkAtoms::src, aSrc, aTriggeringPrincipal, aError);
   }
-  void GetSrcset(nsAString& aSrcset)
+  void GetSrcset(nsAString& aSrcset, nsIPrincipal&)
   {
     GetHTMLAttr(nsGkAtoms::srcset, aSrcset);
   }
-  void SetSrcset(const nsAString& aSrcset, ErrorResult& aError)
+  void SetSrcset(const nsAString& aSrcset, nsIPrincipal& aTriggeringPrincipal, ErrorResult& aError)
   {
-    SetHTMLAttr(nsGkAtoms::srcset, aSrcset, aError);
+    SetHTMLAttr(nsGkAtoms::srcset, aSrcset, aTriggeringPrincipal, aError);
   }
   void GetCrossOrigin(nsAString& aResult)
   {
@@ -427,6 +427,7 @@ private:
   bool mInDocResponsiveContent;
   RefPtr<ImageLoadTask> mPendingImageLoadTask;
   nsCOMPtr<nsIPrincipal> mSrcTriggeringPrincipal;
+  nsCOMPtr<nsIPrincipal> mSrcsetTriggeringPrincipal;
 
   // Last URL that was attempted to load by this element.
   nsCOMPtr<nsIURI> mLastSelectedSource;
diff --git a/dom/webidl/HTMLImageElement.webidl b/dom/webidl/HTMLImageElement.webidl
index 098c31cb6a04..d0cf708caddc 100644
--- a/dom/webidl/HTMLImageElement.webidl
+++ b/dom/webidl/HTMLImageElement.webidl
@@ -23,7 +23,7 @@ interface HTMLImageElement : HTMLElement {
            attribute DOMString alt;
            [CEReactions, NeedsSubjectPrincipal, SetterThrows]
            attribute DOMString src;
-           [CEReactions, SetterThrows]
+           [CEReactions, NeedsSubjectPrincipal, SetterThrows]
            attribute DOMString srcset;
            [CEReactions, SetterThrows]
            attribute DOMString? crossOrigin;
diff --git a/toolkit/components/extensions/test/xpcshell/test_ext_contentscript_triggeringPrincipal.js b/toolkit/components/extensions/test/xpcshell/test_ext_contentscript_triggeringPrincipal.js
index 1c9cdd619fed..01264aba0ff6 100644
--- a/toolkit/components/extensions/test/xpcshell/test_ext_contentscript_triggeringPrincipal.js
+++ b/toolkit/components/extensions/test/xpcshell/test_ext_contentscript_triggeringPrincipal.js
@@ -437,6 +437,11 @@ add_task(async function test_contentscript_triggeringPrincipals() {
       element: ["img", {}],
       src: "img.png",
     },
+    {
+      element: ["img", {}],
+      src: "imgset.png",
+      srcAttr: "srcset",
+    },
   ];
 
   /**