Out-of-bounds Read in Kamailio
CVE-2026-39864
Kamailio is an open source implementation of a SIP Signaling Server. Prior to 6.0.5 and 5.8.7, an out-of-bounds read in the auth module of Kamailio (formerly OpenSER and SER) allows remote attackers to cause a denial of service (process crash) via a specially crafted SIP packet if a successful user authentication without a database backend is followed by additional user identity checks. This vulnerability is fixed in 6.0.5 and 5.8.7.
Vulnerability class: Buffer Overflow
EPSS: 0.003 (22.4th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 4.4 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H.
Affected products
- Kamailio — versions < 5.8.7, >= 6.0.0, < 6.0.5
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-39864?
- CVE-2026-39864 is a medium-severity vulnerability in Kamailio, classified under Out-of-bounds Read. CVSS score: 4.4/10. Published 2026-04-08.
- How severe is CVE-2026-39864?
- Medium severity. CVSS v3 base score is 4.4 out of 10.