# \`cursor-sandbox\` binary missing setuid bit breaks extensions

**URL:** <https://forum.cursor.com/t/cursor-sandbox-binary-missing-setuid-bit-breaks-extensions/147166>\
**Category:** Bug Reports\
**Created:** [December 23, 2025, 5:07pm UTC](https://forum.cursor.com/t/cursor-sandbox-binary-missing-setuid-bit-breaks-extensions/147166 "2025-12-23T17:07:42Z")\
**Posts on this page:** 1\
**Showing post:** 3

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**Author:** ![Colin](https://sea3.discourse-cdn.com/cursor1/user_avatar/forum.cursor.com/colin/32/90452_2.png) [@Colin](https://forum.cursor.com/u/Colin)\
**Post date:** [December 23, 2025, 8:42pm UTC](https://forum.cursor.com/t/cursor-sandbox-binary-missing-setuid-bit-breaks-extensions/147166/3 "2025-12-23T20:42:49Z")

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Hey @Aaron_Smith

Thanks for the investigation over here:

> [@"Activating Extensions" message, extensions don't work -- solution](https://forum.cursor.com/t/activating-extensions-message-extensions-dont-work-solution/146013/):
>
> Where does the bug appear (feature/product)? Cursor IDE Describe the Bug Extensions wouldn’t start because of a problem with the latest Cursor update. If you update Cursor and you run Ubuntu, you may run into this. The problem: Cursor would hang on startup because its sandbox helper (cursor-sandbox) lacked the necessary setuid root permissions, and the system had unprivileged user namespaces disabled (kernel.unprivileged\_userns\_clone=0), preventing the application from properly initializing it…

I’ve flagged this for the team!

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_[View the full topic](https://forum.cursor.com/t/cursor-sandbox-binary-missing-setuid-bit-breaks-extensions/147166)._