Asterisk is an open source private branch exchange and telephony toolkit. From 21.0.0-pre1 until Asterisk 21.12.3, 22.10.1, 23.4.1 and Certified Asterisk 22.8-cert3, the chan_ooh323 Q.931 party-number parser lacks the CVE-2022-37325 fix because that fix was never forward-ported from Asterisk 20 to later versions. Malformed Q.931 elements in an OOH323 request can therefore crash Asterisk. This issue affects Asterisk versions greater than 20. The chan_ooh323 addon channel driver must be explicitly compiled and installed, which is not the default, and its port must be publicly reachable. This issue is fixed in Asterisk 21.12.3, 22.10.1, 23.4.1 and Certified Asterisk 22.8-cert3.