CVE-2023-37457: Digium Asterisk

High severity, CVSS 8.2. EPSS: 1.1% chance of exploitation in the next 30 days.

Asterisk is an open source private branch exchange and telephony toolkit. In Asterisk versions 18.20.0 and prior, 20.5.0 and prior, and 21.0.0; as well as ceritifed-asterisk 18.9-cert5 and prior, the 'update' functionality of the PJSIP_HEADER dialplan function can exceed the available buffer space for storing the new value of a header. By doing so this can overwrite memory or cause a crash. This is not externally exploitable, unless dialplan is explicitly written to update a header based on data from an outside source. If the 'update' functionality is not used the vulnerability does not occur. A patch is available at commit a1ca0268254374b515fa5992f01340f7717113fa.

Affected products

• Digium Asterisk: up to and including 18.20.0; from 19.0.0, up to and including 20.5.0; version 21.0.0 only
• Sangoma Certified Asterisk: version 13.13.0 only; version 16.8.0 only; version 18.9 only

Published 2023-12-14. Last modified 2026-06-17.