# CRITICAL BUG: Memory Leak in Chat/Composer System Causing IDE Crashes **URL:** \ **Category:** Bug Reports\ **Created:** [September 30, 2025, 7:39am UTC](https://forum.cursor.com/t/critical-bug-memory-leak-in-chat-composer-system-causing-ide-crashes/135448 "2025-09-30T07:39:53Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Sumit\_Patil](https://avatars.discourse-cdn.com/v4/letter/s/a698b9/32.png) [@Sumit\_Patil](https://forum.cursor.com/u/Sumit_Patil)\ **Post date:** [September 30, 2025, 7:39am UTC](https://forum.cursor.com/t/critical-bug-memory-leak-in-chat-composer-system-causing-ide-crashes/135448/1 "2025-09-30T07:39:53Z")
### Where does the bug appear (feature/product)? Cursor IDE ### Describe the Bug Cursor IDE is experiencing severe memory leaks in the chat/composer system that cause the extension host to crash and restart repeatedly. The listener count grows exponentially (180 → 459+ listeners) within minutes, leading to complete IDE instability. Environment OS: macOS (darwin 25.0.0) Workspace: Large PHP codebase (~30,000+ files) Extensions: Various (but issue persists even with minimal extensions) ### Steps to Reproduce Open Cursor IDE with a large codebase Use the chat/composer feature for code analysis or file operations Perform multiple tool calls (file writes, code analysis, etc.) Monitor the system for 10-30 minutes IDE will crash and restart ### Expected Behavior Chat/composer should work without memory leaks Extension host should remain stable IDE should not crash during normal usage ### Operating System MacOS ### Current Cursor Version (Menu → About Cursor → Copy) Version: 1.7.23 (Universal) VSCode Version: 1.99.3 Commit: 5069385c5a69db511722405ab5aeadc01579afd0 Date: 2025-09-30T02:52:09.100Z Electron: 34.5.8 Chromium: 132.0.6834.210 Node.js: 20.19.1 V8: 13.2.152.41-electron.0 OS: Darwin arm64 25.0.0 ### For AI issues: which model did you use? Auto ### For AI issues: add Request ID with privacy disabled Request ID: 208bfa27-b034-478f-a2cf-1b2c19b60341 ### Additional Information Timeline of Memory Leak 12:18:10.244 - 180 listeners 12:18:10.249 - 268 listeners (+88 in 5ms) 12:18:10.795 - 274 listeners (+6 in 546ms) 12:20:51.778 - 364 listeners (+90 in 2 minutes) 12:20:53.395 - 459 listeners (+95 in 1.6 seconds) 12:24:54.710 - Extension host terminated unexpectedly Root Cause Analysis The issue is in Cursor’s internal chat/composer system, specifically: Bubble creation system (Pcr.createBubbleFromToolCall) Tool call processing (w7.submitChatMaybeAbortCurrent) Code block processing (Tte.processCodeBlocks) Impact Critical: IDE becomes unusable due to frequent crashes Productivity: Work is lost during crashes Stability: Cannot rely on IDE for development work ### Does this stop you from using Cursor Sometimes - I can sometimes use Cursor ---
**Author:** ![sanjeed5](https://sea3.discourse-cdn.com/cursor1/user_avatar/forum.cursor.com/sanjeed5/32/9610_2.png) [@sanjeed5](https://forum.cursor.com/u/sanjeed5)\ **Post date:** [September 30, 2025, 9:13am UTC](https://forum.cursor.com/t/critical-bug-memory-leak-in-chat-composer-system-causing-ide-crashes/135448/2 "2025-09-30T09:13:58Z")
Thanks for this detailed bug report! Can you please try these: **1. Test in Safe Mode** Run Cursor without extensions to see if the leak persists: ```bash cursor --disable-extensions ``` **2. Check Process Explorer** Open the Process Explorer to see which processes are consuming resources: - `Cmd + Shift + P` → **Developer: Open Process Explorer** - Look specifically at the `extensionHost` processes when the listener count starts climbing - Share a screenshot when you notice the memory leak happening **3. Additional context:** - Which specific chat/composer operations trigger this? (file analysis, code generation, multiple tool calls, etc.) - Does this happen with a smaller/empty workspace, or only your 30K+ file PHP project? ---
**Author:** ![Sumit\_Patil](https://avatars.discourse-cdn.com/v4/letter/s/a698b9/32.png) [@Sumit\_Patil](https://forum.cursor.com/u/Sumit_Patil)\ **Post date:** [September 30, 2025, 11:15am UTC](https://forum.cursor.com/t/critical-bug-memory-leak-in-chat-composer-system-causing-ide-crashes/135448/3 "2025-09-30T11:15:00Z")
Tested in safe mode, but the IDE still crashes. Attached is a screenshot of the output when it happened. **Which operations trigger this?** - Code generation using Agent + Auto mode **Does this happen with smaller/empty workspaces, or only with the 30K+ file PHP project?** - It happens only with larger repos. For smaller repos, it works fine. ![Screenshot 2025-09-30 at 4.16.02 PM](https://us1.discourse-cdn.com/cursor1/original/3X/b/f/bfc629a151a5a9cd14387372bc48eb62d906b2de.png) ![Screenshot 2025-09-30 at 4.17.20 PM](https://us1.discourse-cdn.com/cursor1/original/3X/2/e/2eb3a16a2a0abd7d6a8033c25db7c8c367765110.png) ---
**Author:** ![sanjeed5](https://sea3.discourse-cdn.com/cursor1/user_avatar/forum.cursor.com/sanjeed5/32/9610_2.png) [@sanjeed5](https://forum.cursor.com/u/sanjeed5)\ **Post date:** [October 4, 2025, 5:06pm UTC](https://forum.cursor.com/t/critical-bug-memory-leak-in-chat-composer-system-causing-ide-crashes/135448/4 "2025-10-04T17:06:02Z")
Thanks for sharing the details, I’ve passed it on to the team. ---
**Author:** ![oknrd](https://avatars.discourse-cdn.com/v4/letter/o/a587f6/32.png) [@oknrd](https://forum.cursor.com/u/oknrd)\ **Post date:** [October 24, 2025, 12:57pm UTC](https://forum.cursor.com/t/critical-bug-memory-leak-in-chat-composer-system-causing-ide-crashes/135448/6 "2025-10-24T12:57:31Z")
I’m running cursor on Ubuntu (22) VM with a large code-base. I was using 1.4x and then upgraded to 1.7.53 and I started noticing that cursor UI freezes suddenly and locks-up the VM. The VM needs to be rebooted by force. Something has gone terribly wrong underneath. What I also observe that when cursor is closed, the RAM consumed does not get freed-up. I updated to 1.7.54, then same problems occur though with a bit less frequency. Time to lockup after launch is unpredictable. Sometimes it happens in 10 seconds, sometimes in the middle of chat session after couple of minutes. ---
**Author:** ![cocode](https://sea3.discourse-cdn.com/cursor1/user_avatar/forum.cursor.com/cocode/32/83970_2.png) [@cocode](https://forum.cursor.com/u/cocode)\ **Post date:** [October 24, 2025, 1:26pm UTC](https://forum.cursor.com/t/critical-bug-memory-leak-in-chat-composer-system-causing-ide-crashes/135448/7 "2025-10-24T13:26:31Z")
VM contra Host machine access rights “ **can** ” cause this. ---
**Author:** ![oknrd](https://avatars.discourse-cdn.com/v4/letter/o/a587f6/32.png) [@oknrd](https://forum.cursor.com/u/oknrd)\ **Post date:** [October 27, 2025, 9:56am UTC](https://forum.cursor.com/t/critical-bug-memory-leak-in-chat-composer-system-causing-ide-crashes/135448/8 "2025-10-27T09:56:38Z")
Has anyone from cursor dev team looking into this? ---
**Author:** ![Sumit\_Patil](https://avatars.discourse-cdn.com/v4/letter/s/a698b9/32.png) [@Sumit\_Patil](https://forum.cursor.com/u/Sumit_Patil)\ **Post date:** [November 13, 2025, 6:25am UTC](https://forum.cursor.com/t/critical-bug-memory-leak-in-chat-composer-system-causing-ide-crashes/135448/9 "2025-11-13T06:25:14Z")
It looks like this issue has been resolved in the latest Cursor release — [version 2.0](https://cursor.com/changelog/2-0). I haven’t encountered it since updating. ---
**Author:** ![system](https://sea3.discourse-cdn.com/cursor1/user_avatar/forum.cursor.com/system/32/99069_2.png) [@system](https://forum.cursor.com/u/system)\ **Post date:** [December 5, 2025, 6:25am UTC](https://forum.cursor.com/t/critical-bug-memory-leak-in-chat-composer-system-causing-ide-crashes/135448/10 "2025-12-05T06:25:39Z")
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