Encountered several times in the last days on my fresh F43 installation.
Reporting as it seems like some missing rule for systemd.

-----------------------------------

SELinux is preventing blocking-2 from write access on the sock_file io.systemd.DynamicUser.

*****  Plugin catchall (100. confidence) suggests   **************************

If you believe that blocking-2 should be allowed write access on the io.systemd.DynamicUser sock_file by default.
Then you should report this as a bug.
You can generate a local policy module to allow this access.
Do
allow this access for now by executing:
# ausearch -c 'blocking-2' --raw | audit2allow -M my-blocking2
# semodule -X 300 -i my-blocking2.pp

Additional Information:
Source Context                unconfined_u:unconfined_r:thumb_t:s0-s0:c0.c1023
Target Context                system_u:object_r:systemd_userdbd_runtime_t:s0
Target Objects                io.systemd.DynamicUser [ sock_file ]
Source                        blocking-2
Source Path                   blocking-2
Port                          <Unknown>
Host                          FARAMOS-PC
Source RPM Packages           
Target RPM Packages           
SELinux Policy RPM            selinux-policy-targeted-42.14-1.fc43.noarch
Local Policy RPM              selinux-policy-targeted-42.14-1.fc43.noarch
Selinux Enabled               True
Policy Type                   targeted
Enforcing Mode                Enforcing
Host Name                     FARAMOS-PC
Platform                      Linux FARAMOS-PC 6.17.6-300.fc43.x86_64 #1 SMP
                              PREEMPT_DYNAMIC Wed Oct 29 20:10:51 UTC 2025
                              x86_64
Alert Count                   2
First Seen                    2025-11-05 15:40:53 CET
Last Seen                     2025-11-05 15:40:53 CET
Local ID                      91bb4a75-d2e2-472d-807d-494c1acd4baa

Raw Audit Messages
type=AVC msg=audit(1762353653.977:180): avc:  denied  { write } for  pid=7362 comm="blocking-2" name="io.systemd.DynamicUser" dev="tmpfs" ino=1328 scontext=unconfined_u:unconfined_r:thumb_t:s0-s0:c0.c1023 tcontext=system_u:object_r:systemd_userdbd_runtime_t:s0 tclass=sock_file permissive=0


Hash: blocking-2,thumb_t,systemd_userdbd_runtime_t,sock_file,write


Reproducible: Didn't try