diff --git a/src/stores/executionStore.test.ts b/src/stores/executionStore.test.ts
index ddc552b3f3..e208b452f3 100644
--- a/src/stores/executionStore.test.ts
+++ b/src/stores/executionStore.test.ts
@@ -1,7 +1,7 @@
 import { setActivePinia } from 'pinia'
 import { beforeEach, describe, expect, it, vi } from 'vitest'
 import { app } from '@/scripts/app'
-import { useExecutionStore } from '@/stores/executionStore'
+import { MAX_PROGRESS_JOBS, useExecutionStore } from '@/stores/executionStore'
 import { useExecutionErrorStore } from '@/stores/executionErrorStore'
 import { executionIdToNodeLocatorId } from '@/utils/graphTraversalUtil'
 
@@ -11,6 +11,7 @@ const mockNodeIdToNodeLocatorId = vi.fn()
 const mockNodeLocatorIdToNodeExecutionId = vi.fn()
 
 import type * as WorkflowStoreModule from '@/platform/workflow/management/stores/workflowStore'
+import type { NodeProgressState } from '@/schemas/apiSchema'
 import { createMockLGraphNode } from '@/utils/__tests__/litegraphTestUtils'
 import { createTestingPinia } from '@pinia/testing'
 
@@ -40,6 +41,37 @@ vi.mock('@/composables/node/useNodeProgressText', () => ({
   })
 }))
 
+/**
+ * Captures event handlers registered via api.addEventListener so tests
+ * can invoke them directly (e.g. to simulate WebSocket progress events).
+ */
+type EventHandler = (...args: unknown[]) => void
+const apiEventHandlers = new Map<string, EventHandler>()
+vi.mock('@/scripts/api', () => ({
+  api: {
+    addEventListener: vi.fn((event: string, handler: EventHandler) => {
+      apiEventHandlers.set(event, handler)
+    }),
+    removeEventListener: vi.fn((event: string) => {
+      apiEventHandlers.delete(event)
+    }),
+    clientId: 'test-client',
+    apiURL: vi.fn((path: string) => `/api${path}`)
+  }
+}))
+
+vi.mock('@/stores/imagePreviewStore', () => ({
+  useNodeOutputStore: () => ({
+    revokePreviewsByExecutionId: vi.fn()
+  })
+}))
+
+vi.mock('@/stores/jobPreviewStore', () => ({
+  useJobPreviewStore: () => ({
+    clearPreview: vi.fn()
+  })
+}))
+
 // Mock the app import with proper implementation
 vi.mock('@/scripts/app', () => ({
   app: {
@@ -270,6 +302,92 @@ describe('useExecutionStore - nodeLocationProgressStates caching', () => {
   })
 })
 
+describe('useExecutionStore - nodeProgressStatesByJob eviction', () => {
+  let store: ReturnType<typeof useExecutionStore>
+
+  function makeProgressNodes(
+    nodeId: string,
+    jobId: string
+  ): Record<string, NodeProgressState> {
+    return {
+      [nodeId]: {
+        value: 5,
+        max: 10,
+        state: 'running',
+        node_id: nodeId,
+        prompt_id: jobId,
+        display_node_id: nodeId
+      }
+    }
+  }
+
+  function fireProgressState(
+    jobId: string,
+    nodes: Record<string, NodeProgressState>
+  ) {
+    const handler = apiEventHandlers.get('progress_state')
+    if (!handler) throw new Error('progress_state handler not bound')
+    handler(
+      new CustomEvent('progress_state', { detail: { nodes, prompt_id: jobId } })
+    )
+  }
+
+  beforeEach(() => {
+    vi.clearAllMocks()
+    apiEventHandlers.clear()
+    setActivePinia(createTestingPinia({ stubActions: false }))
+    store = useExecutionStore()
+    store.bindExecutionEvents()
+  })
+
+  it('should retain entries below the limit', () => {
+    for (let i = 0; i < 5; i++) {
+      fireProgressState(`job-${i}`, makeProgressNodes(`${i}`, `job-${i}`))
+    }
+
+    expect(Object.keys(store.nodeProgressStatesByJob)).toHaveLength(5)
+  })
+
+  it('should evict oldest entries when exceeding MAX_PROGRESS_JOBS', () => {
+    for (let i = 0; i < MAX_PROGRESS_JOBS + 10; i++) {
+      fireProgressState(`job-${i}`, makeProgressNodes(`${i}`, `job-${i}`))
+    }
+
+    const keys = Object.keys(store.nodeProgressStatesByJob)
+    expect(keys).toHaveLength(MAX_PROGRESS_JOBS)
+    // Oldest jobs (0-9) should be evicted; newest should remain
+    expect(keys).not.toContain('job-0')
+    expect(keys).not.toContain('job-9')
+    expect(keys).toContain(`job-${MAX_PROGRESS_JOBS + 9}`)
+    expect(keys).toContain(`job-${MAX_PROGRESS_JOBS}`)
+  })
+
+  it('should keep the most recently added job after eviction', () => {
+    for (let i = 0; i < MAX_PROGRESS_JOBS + 1; i++) {
+      fireProgressState(`job-${i}`, makeProgressNodes(`${i}`, `job-${i}`))
+    }
+
+    const lastJobId = `job-${MAX_PROGRESS_JOBS}`
+    expect(store.nodeProgressStatesByJob).toHaveProperty(lastJobId)
+  })
+
+  it('should not evict when updating an existing job', () => {
+    for (let i = 0; i < MAX_PROGRESS_JOBS; i++) {
+      fireProgressState(`job-${i}`, makeProgressNodes(`${i}`, `job-${i}`))
+    }
+    expect(Object.keys(store.nodeProgressStatesByJob)).toHaveLength(
+      MAX_PROGRESS_JOBS
+    )
+
+    // Update an existing job — should not trigger eviction
+    fireProgressState('job-0', makeProgressNodes('0', 'job-0'))
+    expect(Object.keys(store.nodeProgressStatesByJob)).toHaveLength(
+      MAX_PROGRESS_JOBS
+    )
+    expect(store.nodeProgressStatesByJob).toHaveProperty('job-0')
+  })
+})
+
 describe('useExecutionStore - reconcileInitializingJobs', () => {
   let store: ReturnType<typeof useExecutionStore>
 
diff --git a/src/stores/executionStore.ts b/src/stores/executionStore.ts
index 159878d523..41b8158353 100644
--- a/src/stores/executionStore.ts
+++ b/src/stores/executionStore.ts
@@ -46,6 +46,13 @@ interface QueuedJob {
   workflow?: ComfyWorkflow
 }
 
+/**
+ * Maximum number of job entries retained in {@link nodeProgressStatesByJob}.
+ * When exceeded, the oldest entries (by insertion order) are evicted to
+ * prevent unbounded memory growth in long-running sessions.
+ */
+export const MAX_PROGRESS_JOBS = 1000
+
 export const useExecutionStore = defineStore('execution', () => {
   const workflowStore = useWorkflowStore()
   const canvasStore = useCanvasStore()
@@ -297,6 +304,34 @@ export const useExecutionStore = defineStore('execution', () => {
     }
   }
 
+  /**
+   * Evicts the oldest entries from {@link nodeProgressStatesByJob} when the
+   * map exceeds {@link MAX_PROGRESS_JOBS}, preventing unbounded memory
+   * growth in long-running sessions.
+   *
+   * Relies on ES2015+ object key insertion order: the first keys returned
+   * by `Object.keys` are the oldest entries.
+   *
+   * @example
+   * ```ts
+   * // Given 105 entries, evicts the 5 oldest:
+   * evictOldProgressJobs()
+   * Object.keys(nodeProgressStatesByJob.value).length // => 100
+   * ```
+   */
+  function evictOldProgressJobs() {
+    const current = nodeProgressStatesByJob.value
+    const keys = Object.keys(current)
+    if (keys.length <= MAX_PROGRESS_JOBS) return
+
+    const pruned: Record<string, Record<string, NodeProgressState>> = {}
+    const keysToKeep = keys.slice(keys.length - MAX_PROGRESS_JOBS)
+    for (const key of keysToKeep) {
+      pruned[key] = current[key]
+    }
+    nodeProgressStatesByJob.value = pruned
+  }
+
   function handleProgressState(e: CustomEvent<ProgressStateWsMessage>) {
     const { nodes, prompt_id: jobId } = e.detail
 
@@ -319,6 +354,7 @@ export const useExecutionStore = defineStore('execution', () => {
       ...nodeProgressStatesByJob.value,
       [jobId]: nodes
     }
+    evictOldProgressJobs()
     nodeProgressStates.value = nodes
 
     // If we have progress for the currently executing node, update it for backwards compatibility