# CVE-2026-39864: Kamailio out-of-bounds read in auth module

Source: https://junglewise.ai/threats/cve-2026-39864-kamailio-out-of-bounds-read-in-auth-module  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-04-08. Updated: 2026-07-24  
License: CC BY 4.0 with a link back

CVE-2026-39864 · Severity: medium · CVSS 4.4 · Published 2026-04-08

Kamailio is an open-source SIP server used for managing internet-based voice and video communications. A vulnerability in its authentication module allows an attacker to crash the server by sending a specially crafted communication packet. This could lead to a service outage, though it requires the attacker to already have valid user credentials and only affects specific configurations that do not use a database for authentication.

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

## Quick answers

**Is CVE-2026-39864 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-39864 being exploited in the wild.

**How severe is CVE-2026-39864?** Medium severity, with a CVSS score of 4.4, published 8 April 2026.

**Which products and versions are affected?** Kamailio < 5.8.7, >= 6.0.0 < 6.0.5.

**Is there a fix for CVE-2026-39864?** 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-2026-39864 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-39864?** 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

An out-of-bounds read vulnerability exists in the auth.so module of Kamailio. The flaw is triggered when a successful RFC2617 user authentication occurs without a database backend, followed by additional user identity checks. A remote attacker with high privileges (authenticated user) can exploit this by sending a specially crafted SIP packet, leading to a process crash and denial of service. The vulnerability is rooted in how the module handles memory during identity verification in non-database configurations. It is fixed in versions 5.8.7 and 6.0.5.

## Affected products

- Kamailio Kamailio < 5.8.7, >= 6.0.0 < 6.0.5

## Timeline

- 2026-04-07: advisory: GitHub advisory published by vendor
- 2026-04-08: disclosed: CVE published to NVD

## References

- [https://github.com/kamailio/kamailio/security/advisories/GHSA-6m86-m342-g48m](https://github.com/kamailio/kamailio/security/advisories/GHSA-6m86-m342-g48m)

## Related threats

- [Kamailio stack buffer overflow in ims_qos_npn module](https://junglewise.ai/threats/cve-2026-106804-a-stack-based-buffer-overflow-exists-in-kamailio-v6-1-3-and-v6-1)
- [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)