Asterisk is an open source private branch exchange and telephony toolkit. Prior to Asterisk 20.20.1, 21.12.3, 22.10.1, 23.4.1 and Certified Asterisk 22.8-cert3, an authenticated attacker with read-only permissions for the "Asterisk REST Interface (ARI)" may, under certain conditions, execute write operations through "REST-over-WebSocket". The authorization bypass permits "arbitrary module path" loading and conditional remote code execution. The Asterisk HTTP web server must be enabled and reachable, and the attacker must already have valid "read-only ARI credentials". HTTP is disabled by default and binds only to 127.0.0.1 by default even when enabled. This issue is fixed in Asterisk 20.20.1, 21.12.3, 22.10.1, 23.4.1 and Certified Asterisk 22.8-cert3.