BUILD FAILED: Permission denied, Failed to open the file ruby-x.x.x.tar.gz. Kubuntu 24.04

[ksimmi]

Hi.

I can't to install any ruby version.

$ rbenv install 3.4.5
==> Downloading ruby-3.4.5.tar.gz...
-> curl -q -fL -o ruby-3.4.5.tar.gz https://cache.ruby-lang.org/pub/ruby/3.4/ruby-3.4.5.tar.gz
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
0 22.1M 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0Warning: Failed to open the file ruby-3.4.5.tar.gz: Permission denied
0 22.1M 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0
curl: (23) client returned ERROR on write of 16375 bytes
error: failed to download ruby-3.4.5.tar.gz

BUILD FAILED (Ubuntu 24.04 on x86_64 using ruby-build 20250716)

[ksimmi]

The issue turned out to be that curl was installed via Snap. Due to Snap's sandboxing restrictions, it didn’t have proper access to /tmp, which caused the write error (status 23). The solution was to remove the Snap version and install the native one using APT:

sudo snap remove curl  
sudo apt install curl

After switching to the APT version of curl, the ruby-build installation completed without any problems.