An issue was discovered in Asterisk Open Source through 13.27.0, 14.x and 15.x through 15.7.2, and 16.x through 16.4.0, and Certified Asterisk through 13.21-cert3. A pointer dereference in chan_sip while handling SDP negotiation allows an attacker to crash Asterisk when handling an SDP answer to an outgoing T.38 re-invite. To exploit this vulnerability an attacker must cause the chan_sip module to send a T.38 re-invite request to them. Upon receipt, the attacker must send an SDP answer containing both a T.38 UDPTL stream and another media stream containing only a codec (which is not permitted according to the chan_sip configuration).
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alpine Linux | — | Upgrade asterisk | Jan 2, 2020 | Jul 12, 2019 |
| Debian | — | Upgrade asterisk | Dec 2, 2019 | Jul 12, 2019 |
| Freebsd | — | Upgrade asterisk13Upgrade asterisk16Upgrade asterisk15 | Jul 13, 2019 | Jul 12, 2019 |
| Ubuntu | — | No solution exists | Jun 26, 2025 | Jul 12, 2019 |
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