CVE-2025-47779: Using malformed From header can forge identity with ";" or NULL in name portion

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2025-05-22 · updated 2026-06-17
Weakness: CWE-140

Description

Asterisk is an open-source private branch exchange (PBX). Prior to versions 18.26.2, 20.14.1, 21.9.1, and 22.4.1 of Asterisk and versions 18.9-cert14 and 20.7-cert5 of certified-asterisk, SIP requests of the type MESSAGE (RFC 3428) authentication do not get proper alignment. An authenticated attacker can spoof any user identity to send spam messages to the user with their authorization token. Abuse of this security issue allows authenticated attackers to send fake chat messages can be spoofed to appear to come from trusted entities. Even administrators who follow Security best practices and Security Considerations can be impacted. Therefore, abuse can lead to spam and enable social engineering, phishing and similar attacks. Versions 18.26.2, 20.14.1, 21.9.1, and 22.4.1 of Asterisk and versions 18.9-cert14 and 20.7-cert5 of certified-asterisk fix the issue.

Affected products

asterisk: before 18.26.2; from 20.0.0 before 20.14.1; from 21.0.0 before 21.9.1; from 22.0.0 before 22.4.1 — fixed in 18.26.2, 20.14.1, 21.9.1, 22.4.1
Sangoma Certified Asterisk: before 18.9; 18.9, 18.9-cert1, 18.9-cert1-rc1, 18.9-cert10, 18.9-cert11, 18.9-cert12 (+17) — fixed in 18.9

How to fix

Upgrade to a fixed version: asterisk 18.26.2, 20.14.1, 21.9.1, 22.4.1; Sangoma Certified Asterisk 18.9. Check the vendor advisory for mitigations.

References

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