CVE-2026-57191: Asterisk: Stack buffer overflow in MWI NOTIFY Message-Account parsing

High severity · published Oct 27, 2026

CVE-2026-57191

Asterisk: Stack buffer overflow in MWI NOTIFY Message-Account parsing

New

8.2

CVSS

0.6%

EPSS

On KEV

Description

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 unbounded `sscanf` in `res_pjsip_pubsub` when parsing the `MWI NOTIFY` `Message-Account` field may allow an unauthenticated attacker to send a carefully crafted packet that causes a stack buffer overflow and corrupts the underlying transport, permanently disabling all SIP functionality. An Asterisk restart is required to restore full operation. 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.

Exploitation

Is it being used?

Exploit prediction (EPSS)0.6% · higher than 48% of CVEs

Exploited in the wildNo evidence yet

CISA KEVNot listed

Ransomware campaign useNot known

Affected products

Which versions

asterisk · asterisk

< 20.20.1; >= 21.0.0-pre1, < 21.12.3; >= 22.0.0-pre1, < 22.10.1; >= 23.0.0-pre1, < 23.4.1 · source: vendor

certified-asterisk · asterisk

< 20.7-cert11; >= 22.8-cert1-pre1, < 22.8-cert3 · source: vendor