Executive brief
Kamailio is an open-source server used for managing internet-based phone calls and messaging (SIP signaling). A vulnerability has been identified where a remote attacker can send a malicious data packet to the server, causing it to crash. This results in a denial of service, potentially disrupting communication services for all users until the system is restored.
Technical details
An out-of-bounds access vulnerability (CWE-119) exists in the core TCP data processing component of Kamailio. The flaw is triggered when the server processes a specially crafted data packet sent over a TCP or TLS connection. A remote, unauthenticated attacker can exploit this to cause a process crash, leading to a denial of service (DoS). The vulnerability affects Kamailio instances configured with TCP or TLS listeners. Patches have been released in versions 5.8.8, 6.0.6, and 6.1.1 to address the improper restriction of operations within memory buffer bounds.
Affected products
- Kamailio Kamailio SIP Server < 5.8.8, 6.0.0 to < 6.0.6, 6.1.0 to < 6.1.1
Timeline
- 2026-04-07: advisory: GitHub Security Advisory published by vendor
- 2026-04-08: disclosed: CVE published to NVD
- 2026-04-08: patched: Fixes available in versions 5.8.8, 6.0.6, and 6.1.1