Buffer overflow in Asterisk

CVE-2026-57194

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 20.7-cert11, 22.8-cert3, an out-of-bounds write in `chan_unistim` `DIALPAGE` digit handling can overflow the `phone_number` field and crash Asterisk when an attacker sends a carefully crafted incoming request packet. The `chan_unistim` module must be loaded and configured with a valid `UNISTIM UDP port` that the attacker can reach. The attacker must register as a configured `phone MAC`, or the deployment must have an equivalent `production/autoprovisioning` path that allows the client to reach the main page. This issue is fixed in Asterisk 20.20.1, 21.12.3, 22.10.1, 23.4.1 and Certified Asterisk 20.7-cert11, 22.8-cert3.

Vulnerability class: Buffer Overflow

Published .

CVSS v3 metric

CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-57194?
CVE-2026-57194 is a medium-severity vulnerability in Asterisk, classified under Out-of-bounds Write. CVSS score: 5.9/10. Published 2026-10-27.
How severe is CVE-2026-57194?
Medium severity. CVSS v3 base score is 5.9 out of 10.