diff --git a/packages/vite/src/node/plugins/css.ts b/packages/vite/src/node/plugins/css.ts
index 3ffd93bb9f9910..c13a4c83052639 100644
--- a/packages/vite/src/node/plugins/css.ts
+++ b/packages/vite/src/node/plugins/css.ts
@@ -1045,18 +1045,26 @@ function rewriteImportCss(
   })
 }
 
-function rewriteCssImageSet(
+// TODO: image and cross-fade could contain a "url" that needs to be processed
+// https://drafts.csswg.org/css-images-4/#image-notation
+// https://drafts.csswg.org/css-images-4/#cross-fade-function
+const cssNotProcessedRE = /(gradient|element|cross-fade|image)\(/
+
+async function rewriteCssImageSet(
   css: string,
   replacer: CssUrlReplacer
 ): Promise<string> {
-  return asyncReplace(css, cssImageSetRE, async (match) => {
+  return await asyncReplace(css, cssImageSetRE, async (match) => {
     const [, rawUrl] = match
     const url = await processSrcSet(rawUrl, async ({ url }) => {
       // the url maybe url(...)
       if (cssUrlRE.test(url)) {
         return await rewriteCssUrls(url, replacer)
       }
-      return await doUrlReplace(url, url, replacer)
+      if (!cssNotProcessedRE.test(url)) {
+        return await doUrlReplace(url, url, replacer)
+      }
+      return url
     })
     return url
   })
diff --git a/packages/vite/src/node/utils.ts b/packages/vite/src/node/utils.ts
index ddcaced9832bc1..0c25b4592adf6d 100644
--- a/packages/vite/src/node/utils.ts
+++ b/packages/vite/src/node/utils.ts
@@ -560,8 +560,7 @@ export async function processSrcSet(
   srcs: string,
   replacer: (arg: ImageCandidate) => Promise<string>
 ): Promise<string> {
-  const imageCandidates: ImageCandidate[] = srcs
-    .split(',')
+  const imageCandidates: ImageCandidate[] = splitSrcSet(srcs)
     .map((s) => {
       const src = s.replace(escapedSpaceCharacters, ' ').trim()
       const [url] = imageSetUrlRE.exec(src) || []
@@ -589,6 +588,25 @@ export async function processSrcSet(
   }, '')
 }
 
+function splitSrcSet(srcs: string) {
+  const parts: string[] = []
+  // There could be a ',' inside of url(data:...), linear-gradient(...) or "data:..."
+  const cleanedSrcs = srcs.replace(
+    /(?:url|image|gradient|cross-fade)\([^\)]*\)|"([^"]|(?<=\\)")*"|'([^']|(?<=\\)')*'/g,
+    blankReplacer
+  )
+  let startIndex = 0
+  let splitIndex: number
+  do {
+    splitIndex = cleanedSrcs.indexOf(',', startIndex)
+    parts.push(
+      srcs.slice(startIndex, splitIndex !== -1 ? splitIndex : undefined)
+    )
+    startIndex = splitIndex + 1
+  } while (splitIndex !== -1)
+  return parts
+}
+
 function escapeToLinuxLikePath(path: string) {
   if (/^[A-Z]:/.test(path)) {
     return path.replace(/^([A-Z]):\//, '/windows/$1/')
diff --git a/playground/assets/__tests__/assets.spec.ts b/playground/assets/__tests__/assets.spec.ts
index c63ffc7cc1c0c2..d9f1c8ed761773 100644
--- a/playground/assets/__tests__/assets.spec.ts
+++ b/playground/assets/__tests__/assets.spec.ts
@@ -118,8 +118,23 @@ describe('css url() references', () => {
     })
   })
 
-  // not supported in browser now
+  test('image-set with base64', async () => {
+    const imageSet = await getBg('.css-image-set-base64')
+    expect(imageSet).toMatch(
+      `-webkit-image-set(url("data:image/png;base64,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") 1x, url("data:image/png;base64,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") 2x)`
+    )
+  })
+
+  // TODO: not supported in chrome
   // https://drafts.csswg.org/css-images-4/#image-set-notation
+  //
+  // test('image-set with multiple descriptor', async () => {
+  //   const imageSet = await getBg('.css-image-set-gradient')
+  //   expect(imageSet).toMatch(
+  //     `-webkit-image-set(url("data:image/png;base64,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") 1x, linear-gradient(#e66465, #9198e5) 2x)`
+  //   )
+  // })
+  //
   // test('image-set with multiple descriptor', async () => {
   //   const imageSet = await getBg('.css-image-set-multiple-descriptor')
   //   imageSet.split(', ').forEach((s) => {
diff --git a/playground/assets/css/css-url.css b/playground/assets/css/css-url.css
index 9047cd384e7d38..1446f19afa662e 100644
--- a/playground/assets/css/css-url.css
+++ b/playground/assets/css/css-url.css
@@ -41,6 +41,25 @@
   background-size: 10px;
 }
 
+.css-image-set-base64 {
+  background-image: -webkit-image-set(
+    url(data:image/png;base64,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)
+      1x,
+    url(data:image/png;base64,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)
+      2x
+  );
+  background-size: 10px;
+}
+
+.css-image-set-gradient {
+  background-image: -webkit-image-set(
+    'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAADwAAAA0AgMAAACrwbOMAAADI2lUWHRYTUw6Y29tLmFkb2JlLnhtcAAAAAAAPD94cGFja2V0IGJlZ2luPSLvu78iIGlkPSJXNU0wTXBDZWhpSHpyZVN6TlRjemtjOWQiPz4gPHg6eG1wbWV0YSB4bWxuczp4PSJhZG9iZTpuczptZXRhLyIgeDp4bXB0az0iQWRvYmUgWE1QIENvcmUgNS42LWMxMzggNzkuMTU5ODI0LCAyMDE2LzA5LzE0LTAxOjA5OjAxICAgICAgICAiPiA8cmRmOlJERiB4bWxuczpyZGY9Imh0dHA6Ly93d3cudzMub3JnLzE5OTkvMDIvMjItcmRmLXN5bnRheC1ucyMiPiA8cmRmOkRlc2NyaXB0aW9uIHJkZjphYm91dD0iIiB4bWxuczp4bXBNTT0iaHR0cDovL25zLmFkb2JlLmNvbS94YXAvMS4wL21tLyIgeG1sbnM6c3RSZWY9Imh0dHA6Ly9ucy5hZG9iZS5jb20veGFwLzEuMC9zVHlwZS9SZXNvdXJjZVJlZiMiIHhtbG5zOnhtcD0iaHR0cDovL25zLmFkb2JlLmNvbS94YXAvMS4wLyIgeG1wTU06RG9jdW1lbnRJRD0ieG1wLmRpZDo1MDI2QjVGQTg3RUIxMUVBQUFDMkQ3NTM0MUZGNzU3RSIgeG1wTU06SW5zdGFuY2VJRD0ieG1wLmlpZDo1MDI2QjVGOTg3RUIxMUVBQUFDMkQ3NTM0MUZGNzU3RSIgeG1wOkNyZWF0b3JUb29sPSJBZG9iZSBQaG90b3Nob3AgQ0MgKE1hY2ludG9zaCkiPiA8eG1wTU06RGVyaXZlZEZyb20gc3RSZWY6aW5zdGFuY2VJRD0ieG1wLmlpZDpBNzc3MDZDRjg3QUIxMUUzQjcwREVFMDM3NzA2QzEyMyIgc3RSZWY6ZG9jdW1lbnRJRD0ieG1wLmRpZDpBNzc3MDZEMDg3QUIxMUUzQjcwREVFMDM3NzA2QzEyMyIvPiA8L3JkZjpEZXNjcmlwdGlvbj4gPC9yZGY6UkRGPiA8L3g6eG1wbWV0YT4gPD94cGFja2V0IGVuZD0iciI/PqfCcbEAAAAZdEVYdFNvZnR3YXJlAEFkb2JlIEltYWdlUmVhZHlxyWU8AAAADFBMVEVBuoQ0R10/qn8/qX7FyuqbAAAABHRSTlP9/QGEiU0+GwAAAPtJREFUGBkFwbFNXEEUBdDD/QSWmE7YYAogWNeAaMfaEuiD5HfAk9yIAwqYwIGRRvt8zkNdvckrzzcfjqDccdPIYnH1AJ4ywLs7m53Fhkcw0+DLDxZn0PCHQrrg2xWOCpS7m6bFAj/ZDLFY/AJbDDZ/WUzR4B84BRoURBeAo4Si0CBMFvBEGMBmExYbi0loACcBjQKhC3AUQVGaRjBhMxAsFlwQDLYFBA04EaAVEHSBoxAoPmkITBYDAovNhsAAEwINTggAINCFoyCg0CBgYoCAjQsIACCgcYKABhCgHAUClAYCTAMIsF2AAAACtBMIQAEB+jcggE9AAC+A/zyyZDSXstCbAAAAAElFTkSuQmCC'
+      1x,
+    linear-gradient(#e66465, #9198e5) 2x
+  );
+  background-size: 10px;
+}
+
 .css-image-set-multiple-descriptor {
   background-image: -webkit-image-set(
     '../nested/asset.png' type('image/png') 1x,
diff --git a/playground/assets/index.html b/playground/assets/index.html
index 43eed55236abd3..fcf0e4ce1e81d7 100644
--- a/playground/assets/index.html
+++ b/playground/assets/index.html
@@ -56,6 +56,16 @@ <h2>CSS url references</h2>
     CSS background image-set() (mix var and url)
   </span>
 </div>
+<div class="css-image-set-base64">
+  <span style="background: #fff">
+    CSS background image-set() (with base64)
+  </span>
+</div>
+<div class="css-image-set-gradient">
+  <span style="background: #fff">
+    CSS background image-set() (with gradient)
+  </span>
+</div>
 <div class="css-image-set-multiple-descriptor">
   <span style="background: #fff">
     CSS background image-set() (with multiple descriptor)