Is CVE-2026-57191 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-57191 being exploited in the wild.

How severe is CVE-2026-57191?

Informational severity, published 27 October 2026.

Which products and versions are affected?

Asterisk Project Asterisk before 20.20.1, 21.12.3, 22.10.1, 23.4.1; Asterisk Project Certified Asterisk before 20.7-cert11, 22.8-cert3.

Is there a fix for CVE-2026-57191?

Yes: fixed in Asterisk 20.20.1, 21.12.3, 22.10.1, 23.4.1; Certified Asterisk 20.7-cert11, 22.8-cert3. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-57191 attacked?

It is attacked over the network, in a hosted service.

Am I affected by CVE-2026-57191?

Check whether you run Asterisk Project Asterisk or Asterisk Project Certified Asterisk at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-57191: Asterisk buffer overflow in MWI NOTIFY parser

CVE-2026-57191 · Severity: info · Published 2026-10-27

Asterisk is a telecommunications server that processes phone calls and messaging. An unauthenticated attacker can send a specially crafted SIP message that causes a buffer overflow, permanently disabling all telephone functionality until the server is manually restarted. This allows an attacker to take down phone systems without authentication.

Technologies: Asterisk Project Asterisk, Asterisk Project Certified Asterisk. Vendors: Asterisk Project.

Quick answers

Is CVE-2026-57191 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-57191 being exploited in the wild.
How severe is CVE-2026-57191?: Informational severity, published 27 October 2026.
Which products and versions are affected?: Asterisk Project Asterisk before 20.20.1, 21.12.3, 22.10.1, 23.4.1; Asterisk Project Certified Asterisk before 20.7-cert11, 22.8-cert3.
Is there a fix for CVE-2026-57191?: Yes: fixed in Asterisk 20.20.1, 21.12.3, 22.10.1, 23.4.1; Certified Asterisk 20.7-cert11, 22.8-cert3. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-57191 attacked?: It is attacked over the network, in a hosted service.
Am I affected by CVE-2026-57191?: Check whether you run Asterisk Project Asterisk or Asterisk Project Certified Asterisk at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

Fixed in: Asterisk 20.20.1, 21.12.3, 22.10.1, 23.4.1; Certified Asterisk 20.7-cert11, 22.8-cert3

Technical details

An unbounded sscanf in res_pjsip_pubsub parses the Message-Account field from incoming SIP MWI NOTIFY messages into a 512-byte stack buffer. An unauthenticated attacker can send a NOTIFY with a Message-Account value exceeding 512 bytes, causing a stack buffer overflow that corrupts the PJSIP transport layer. The transport becomes permanently disabled without crashing the process, requiring a manual Asterisk restart to restore SIP functionality.

Affected products

Asterisk Project Asterisk before 20.20.1, 21.12.3, 22.10.1, 23.4.1
Asterisk Project Certified Asterisk before 20.7-cert11, 22.8-cert3

Timeline

2026-10-27: disclosed

References

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