CVE-2026-39863
High
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.
SeverityHigh
CVSS7.5
Exploit probability—
ProductKamailio
PublishedApr 8, 2026
First seenApr 8, 2026
Weakness typeCWE-119Memory buffer bounds error
How to fix
Update
- kamailio kamailio5.8.8, 6.0.6 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| kamailio kamailio | v < 5.8.8, 6.0.0 ≤ v < 6.0.6, 6.1.0 | 5.8.8, 6.0.6 |
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