CVE-2026-39863 Kamailio Core: TCP Data Processing Vulnerability
Remote attackers can crash Kamailio SIP servers via crafted TCP packets due to out-of-bounds memory access, requiring an upgrade to patched versions.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-39863?
CVE-2026-39863 is a high-severity memory corruption vulnerability in kamailio, published on 8 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Kamailio is an open source implementation of a SIP Signaling Server. Prior to 6.1.1, 6.0.6, and 5.8.8, an out-of-bounds access in the core of Kamailio (formerly OpenSER and SER) allows remote attackers to cause a denial of service (process crash) via a specially crafted data packet sent over TCP. The issue impacts Kamailio instances having TCP or TLS listeners. This vulnerability is fixed in 5.1.1, 6.0.6, and 5.8.8.
Weakness: CWE-119
Which versions are affected by CVE-2026-39863?
It affects 1 product.
Products include Kamailio Kamailio.
How do I fix CVE-2026-39863?
Upgrade to a fixed version.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-39863 being exploited?
There is no known exploitation of CVE-2026-39863 in the wild and no public exploit code.
Other vulnerabilities in kamailio
Sources
Also known as ALPINE-CVE-2026-39863, DEBIAN-CVE-2026-39863, GHSA-2wj4-f825-2h2f, UBUNTU-CVE-2026-39863.