CVE-2026-57191 Asterisk: Stack buffer overflow in MWI NOTIFY Message-Account parsing
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-57191?
CVE-2026-57191 is a high-severity vulnerability in asterisk, published on 27 Oct 2026.
Official 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.
Which versions are affected by CVE-2026-57191?
How do I fix CVE-2026-57191?
Upgrade to a fixed version.
Is CVE-2026-57191 being exploited?
There is no known exploitation of CVE-2026-57191 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-57191, GHSA-589g-qgf8-m6mx, UBUNTU-CVE-2026-57191.