# CVE-2026-106804: Kamailio stack buffer overflow in ims_qos_npn module

Source: https://junglewise.ai/threats/cve-2026-106804-a-stack-based-buffer-overflow-exists-in-kamailio-v6-1-3-and-v6-1  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-02. Updated: 2026-11-02  
License: CC BY 4.0 with a link back

CVE-2026-106804 · Severity: info · Published 2026-11-02

Kamailio is open-source VoIP server software used by telecommunications providers to route voice calls in 5G networks (VoNR) and 4G networks (VoLTE). A stack buffer overflow in the ims_qos_npn module allows an attacker to crash the proxy server by sending a malformed SIP registration message, causing the voice network to lose service until the server restarts.

Technologies: [Kamailio](https://junglewise.ai/threats/technologies/kamailio). Vendors: [Kamailio](https://junglewise.ai/threats/vendors/kamailio).

## Quick answers

**Is CVE-2026-106804 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-106804 being exploited in the wild.

**How severe is CVE-2026-106804?** Informational severity, published 2 November 2026.

**Which products and versions are affected?** Kamailio 6.1.3, 6.1.4, master branch.

**Is there a fix for CVE-2026-106804?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-106804 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-106804?** Check whether you run Kamailio 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.

## Technical details

A stack-based buffer overflow exists in the w_rx_aar_register() function within the ims_qos_npn module, where the host field from a SIP Via header is copied into a 46-byte fixed-size buffer without length validation. An unauthenticated remote attacker can send a crafted SIP REGISTER request with an oversized Via host field to overflow the stack, corrupting the return address and causing process termination. The vulnerability affects versions 6.1.3, 6.1.4, and the master branch; a fix exists in the related ims_qos module but was never backported to ims_qos_npn.

## Affected products

- Kamailio Kamailio 6.1.3, 6.1.4, master branch

## Timeline

- 2026-09-23: disclosed
- 2026-11-02: advisory

## References

- [https://gist.github.com/hackeryounow/f5af75502ea6df600428c46bb9bbf39e](https://gist.github.com/hackeryounow/f5af75502ea6df600428c46bb9bbf39e)
- [https://github.com/kamailio/kamailio/issues/4953](https://github.com/kamailio/kamailio/issues/4953)

## Related threats

- [Kamailio stack buffer overflow in ims_registrar_pcscf module](https://junglewise.ai/threats/cve-2026-106803-a-stack-based-buffer-overflow-exists-in-kamailio-v6-1-3-and-v6-1)
- [Kamailio sipt module buffer overflow in ISUP parser](https://junglewise.ai/threats/cve-2026-108822-a-vulnerability-was-detected-in-kamailio-up-to-6-0-7-6-1-3-the)
- [Kamailio heap buffer overflow in CDP Diameter Receiver](https://junglewise.ai/threats/cve-2026-93962-a-weakness-has-been-identified-in-kamailio-up-to-5-8-8-6-0-7-6-1)
- [Kamailio ims_registrar_pcscf double free in security agreement parsing](https://junglewise.ai/threats/cve-2026-52023-kamailio-ims-registrar-pcscf-double-free-in-security-agreement)
- [Kamailio IMS P-CSCF denial of service in REGISTER handling](https://junglewise.ai/threats/cve-2026-52022-kamailio-ims-p-cscf-denial-of-service-in-register-handling)