Yealink SIP-T33G < 124.87.0.0 Race Condition via Diagnostic File Deletion

Yealink SIP-T33G firmware versions 124.86.x.x prior to 124.87.0.0 contain a race condition vulnerability that allows authenticated attackers to interrupt active diagnostic processes by concurrently deleting output files written to predictable paths under the diagnostic directory. Attackers can trigger a diagnostic operation such as traceroute or ping and simultaneously invoke the file deletion endpoint to terminate the running process, leaving the system in an inconsistent state.