I have a setup for isolating Firefox in lxd/incus containers which has been working fine for years. Initially it was based on Ubuntu 20.04 and lxd, but nowadays it uses Ubuntu 24.04 and Incus 6.0.4. After the recent Ubuntu kernel upgrade from Linux 6.11 to 6.14, Firefox cannot make any network connections anymore. The Firefox debugger shows an error message indicating it cannot connect to sockets anymore. BTW: Chrome still works fine with the 6.14 kernel, so it is a very specific issue of the new Ubuntu kernel, Incus and Firefox.
Any ideas what the issue is and how it could be fixed (other than reverting to an older Linux kernel)?