diff --git a/web/src/features/task-plugins/__tests__/marketplace-panel.test.tsx b/web/src/features/task-plugins/__tests__/marketplace-panel.test.tsx
index 1615ee0e5..c5a343b4d 100644
--- a/web/src/features/task-plugins/__tests__/marketplace-panel.test.tsx
+++ b/web/src/features/task-plugins/__tests__/marketplace-panel.test.tsx
@@ -81,6 +81,10 @@ function renderPanel(): QueryClient {
   return queryClient
 }
 
+function requestedUrls(fetchMock: ReturnType<typeof vi.fn>): string[] {
+  return fetchMock.mock.calls.map(([input]) => String(input))
+}
+
 function installIndexFetchMock() {
   const fetchMock = vi.fn(async (input: RequestInfo | URL) => {
     const url = String(input)
@@ -117,8 +121,8 @@ describe('MarketplacePanel source switch', () => {
       'aria-pressed',
       'true'
     )
-    expect(fetchMock).toHaveBeenCalledWith(DEFAULT_MARKETPLACE_INDEX_URL)
-    expect(fetchMock).not.toHaveBeenCalledWith(GITHUB_MARKETPLACE_INDEX_URL)
+    expect(requestedUrls(fetchMock)).toContain(DEFAULT_MARKETPLACE_INDEX_URL)
+    expect(requestedUrls(fetchMock)).not.toContain(GITHUB_MARKETPLACE_INDEX_URL)
   })
 
   test('loads GitHub only after the administrator switches to it', async () => {
@@ -127,7 +131,7 @@ describe('MarketplacePanel source switch', () => {
     renderPanel()
     await screen.findByRole('heading', { name: officialIndex.name })
 
-    expect(fetchMock).not.toHaveBeenCalledWith(GITHUB_MARKETPLACE_INDEX_URL)
+    expect(requestedUrls(fetchMock)).not.toContain(GITHUB_MARKETPLACE_INDEX_URL)
 
     await user.click(screen.getByRole('button', { name: 'GitHub' }))
 
@@ -141,7 +145,7 @@ describe('MarketplacePanel source switch', () => {
       'aria-pressed',
       'true'
     )
-    expect(fetchMock).toHaveBeenCalledWith(GITHUB_MARKETPLACE_INDEX_URL)
+    expect(requestedUrls(fetchMock)).toContain(GITHUB_MARKETPLACE_INDEX_URL)
   })
 
   test('does not request GitHub automatically when the official source fails', async () => {
@@ -158,7 +162,28 @@ describe('MarketplacePanel source switch', () => {
     expect(
       await screen.findByText('Could not load this source')
     ).toBeInTheDocument()
-    expect(fetchMock).toHaveBeenCalledWith(DEFAULT_MARKETPLACE_INDEX_URL)
-    expect(fetchMock).not.toHaveBeenCalledWith(GITHUB_MARKETPLACE_INDEX_URL)
+    expect(requestedUrls(fetchMock)).toContain(DEFAULT_MARKETPLACE_INDEX_URL)
+    expect(requestedUrls(fetchMock)).not.toContain(GITHUB_MARKETPLACE_INDEX_URL)
+  })
+
+  test('revalidates the index instead of reusing a stale browser-cached copy', async () => {
+    const staleIndex: MarketplaceIndex = { ...officialIndex, name: 'Stale' }
+    vi.stubGlobal(
+      'fetch',
+      vi.fn(async (_input: RequestInfo | URL, init?: RequestInit) => {
+        const revalidated = ['no-cache', 'no-store', 'reload'].includes(
+          init?.cache ?? 'default'
+        )
+        return new Response(
+          JSON.stringify(revalidated ? officialIndex : staleIndex),
+          { status: 200 }
+        )
+      })
+    )
+    renderPanel()
+
+    expect(
+      await screen.findByRole('heading', { name: officialIndex.name })
+    ).toBeInTheDocument()
   })
 })
diff --git a/web/src/features/task-plugins/__tests__/marketplace-plugin-logo.test.tsx b/web/src/features/task-plugins/__tests__/marketplace-plugin-logo.test.tsx
index dd25740db..ffa9ad4ef 100644
--- a/web/src/features/task-plugins/__tests__/marketplace-plugin-logo.test.tsx
+++ b/web/src/features/task-plugins/__tests__/marketplace-plugin-logo.test.tsx
@@ -84,7 +84,8 @@ describe('marketplace card logo', () => {
       )
     })
     expect(fetchMock).toHaveBeenCalledWith(
-      'https://raw.githubusercontent.com/QuantumNous/new-api-plugins/main/plugins/tasks/incho/icon.svg'
+      'https://raw.githubusercontent.com/QuantumNous/new-api-plugins/main/plugins/tasks/incho/icon.svg',
+      expect.anything()
     )
   })
 
diff --git a/web/src/features/task-plugins/__tests__/plugin-icon-file.test.ts b/web/src/features/task-plugins/__tests__/plugin-icon-file.test.ts
index c4bd8e491..ba09cb241 100644
--- a/web/src/features/task-plugins/__tests__/plugin-icon-file.test.ts
+++ b/web/src/features/task-plugins/__tests__/plugin-icon-file.test.ts
@@ -111,6 +111,25 @@ describe('fetchPluginIconDataUri', () => {
     )
   })
 
+  test('revalidates with the host so a stale browser-cached logo does not fail the digest', async () => {
+    const result = await fetchPluginIconDataUri(
+      'https://raw.example/plugins/tasks/incho/icon.svg',
+      {
+        sha256:
+          'd4dc56669143034f31aa309635d4113d9ad76a02b1739da22c965ed2049be9e6',
+        fetchImpl: async (_input, init) =>
+          okResponse(
+            ['no-cache', 'no-store', 'reload'].includes(
+              init?.cache ?? 'default'
+            )
+              ? '<svg/>'
+              : '<svg>stale</svg>'
+          ),
+      }
+    )
+    assert.equal(result, 'data:image/svg+xml;base64,PHN2Zy8+')
+  })
+
   test('returns null for a non-image path, a failed response, or a network error', async () => {
     assert.equal(
       await fetchPluginIconDataUri('https://raw.example/icon.js', {
diff --git a/web/src/features/task-plugins/__tests__/plugin-url.test.ts b/web/src/features/task-plugins/__tests__/plugin-url.test.ts
index 3f2e17603..8cd08e42d 100644
--- a/web/src/features/task-plugins/__tests__/plugin-url.test.ts
+++ b/web/src/features/task-plugins/__tests__/plugin-url.test.ts
@@ -213,6 +213,24 @@ describe('browser plugin source fetch', () => {
     )
   })
 
+  test('revalidates with the host instead of reusing a stale browser-cached copy', async () => {
+    // A marketplace host may serve versioned sources as immutable while the
+    // file was republished in place; the stale copy would fail the index hash.
+    const text = await fetchPluginSourceText(
+      'https://example.com/plugin.js',
+      async (_input, init) =>
+        stubResponse({
+          ok: true,
+          body: ['no-cache', 'no-store', 'reload'].includes(
+            init?.cache ?? 'default'
+          )
+            ? 'republished source'
+            : 'stale cached source',
+        })
+    )
+    assert.equal(text, 'republished source')
+  })
+
   test('accepts a body exactly at the limit', async () => {
     const text = await fetchPluginSourceText(
       'https://example.com/limit.js',
diff --git a/web/src/features/task-plugins/components/marketplace-panel.tsx b/web/src/features/task-plugins/components/marketplace-panel.tsx
index b6ac06784..79877c8e0 100644
--- a/web/src/features/task-plugins/components/marketplace-panel.tsx
+++ b/web/src/features/task-plugins/components/marketplace-panel.tsx
@@ -77,7 +77,11 @@ export function MarketplacePanel() {
     meta: { errorToast: false },
     queryFn: async (): Promise<MarketplaceIndex> => {
       if (!selectedSource) throw new Error('marketplace source is not selected')
-      const response = await fetch(selectedSource.index_url)
+      // Revalidate so the hashes checked at install time are the host's
+      // current ones rather than a copy cached before a republish.
+      const response = await fetch(selectedSource.index_url, {
+        cache: 'no-cache',
+      })
       if (!response.ok) {
         throw new Error(
           t('Index request failed with HTTP {{status}}', {
diff --git a/web/src/features/task-plugins/lib/plugin-icon-file.ts b/web/src/features/task-plugins/lib/plugin-icon-file.ts
index cfcca4696..a5d77edc0 100644
--- a/web/src/features/task-plugins/lib/plugin-icon-file.ts
+++ b/web/src/features/task-plugins/lib/plugin-icon-file.ts
@@ -100,7 +100,9 @@ export async function fetchPluginIconDataUri(
   const fetchImpl = options.fetchImpl ?? globalThis.fetch
   let response: Response
   try {
-    response = await fetchImpl(url)
+    // Revalidate so a logo republished in place is not read from a stale
+    // cache and dropped by the digest check.
+    response = await fetchImpl(url, { cache: 'no-cache' })
   } catch {
     return null
   }
diff --git a/web/src/features/task-plugins/lib/plugin-url.ts b/web/src/features/task-plugins/lib/plugin-url.ts
index 6b3e3cf22..2ca7978d3 100644
--- a/web/src/features/task-plugins/lib/plugin-url.ts
+++ b/web/src/features/task-plugins/lib/plugin-url.ts
@@ -90,7 +90,9 @@ export class PluginSourceFetchError extends Error {
 /**
  * Fetches plugin source in the browser. Every marketplace and URL-import fetch
  * goes through here: the gateway never makes the outbound request, so there is
- * no server-side SSRF surface.
+ * no server-side SSRF surface. The request always revalidates with the host:
+ * versioned sources are often served as immutable, and a file republished in
+ * place would otherwise be read from a stale cache and fail the index sha256.
  */
 export async function fetchPluginSourceText(
   url: string,
@@ -98,7 +100,7 @@ export async function fetchPluginSourceText(
 ): Promise<string> {
   let response: Response
   try {
-    response = await fetchImpl(url)
+    response = await fetchImpl(url, { cache: 'no-cache' })
   } catch {
     throw new PluginSourceFetchError('unreachable')
   }