res_pjsip_t38 in Sangoma Asterisk 16.x before 16.16.2, 17.x before 17.9.3, and 18.x before 18.2.2, and Certified Asterisk before 16.8-cert7, allows an attacker to trigger a crash by sending an m=image line and zero port in a response to a T.38 re-invite initiated by Asterisk. This is a re-occurrence of the CVE-2019-15297 symptoms but not for exactly the same reason. The crash occurs because there is an append operation relative to the active topology, but this should instead be a replace operation.
A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Certified_asterisk | Asterisk | 16.8.0 (including) | 16.8.0 (including) |
| Certified_asterisk | Asterisk | 16.8.0-cert1 (including) | 16.8.0-cert1 (including) |
| Certified_asterisk | Asterisk | 16.8.0-cert2 (including) | 16.8.0-cert2 (including) |
| Certified_asterisk | Asterisk | 16.8.0-cert3 (including) | 16.8.0-cert3 (including) |
| Certified_asterisk | Asterisk | 16.8.0-cert4 (including) | 16.8.0-cert4 (including) |
| Certified_asterisk | Asterisk | 16.8.0-cert5 (including) | 16.8.0-cert5 (including) |
| Certified_asterisk | Asterisk | 16.8.0-cert6 (including) | 16.8.0-cert6 (including) |
| Asterisk | Digium | 16.0.0 (including) | 16.16.2 (excluding) |
| Asterisk | Digium | 17.0.0 (including) | 17.9.3 (excluding) |
| Asterisk | Digium | 18.0.0 (including) | 18.2.2 (excluding) |