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Vulnerability record · CVE-2026-39863 · published 8 April 2026

CVE-2026-39863: Kamailio memory buffer overflow vulnerability

Kamailio · Kamailio

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.

7.5 CVSS 3.1 High EPSS 0.55% · top 56.3% CWE-119 · Memory buffer overflow
7.5CVSS 3.1 base score
0.55%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
1References
24 Jul 2026Last modified by NVD

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.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/kamailio/kamailio/security/advisories/GHSA-2wj4-f825-2h2f Vendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2020-27507Kamailio classic buffer overflow vulnerabilityThe Kamailio SIP before 5.5.0 server mishandles INVITE requests with duplicated fields and overlength tag, leading to a buffer overflow that crashes …EPSS 1.2%9.8CVE-2018-16657Debian linux null pointer dereference vulnerabilityIn Kamailio before 5.0.7 and 5.1.x before 5.1.4, a crafted SIP message with an invalid Via header causes a segmentation fault and crashes Kamailio. T…EPSS 3.6%9.8CVE-2018-14767Debian linux improper input validation vulnerabilityIn Kamailio before 5.0.7 and 5.1.x before 5.1.4, a crafted SIP message with a double "To" header and an empty "To" tag causes a segmentation fault an…EPSS 29%9.8CVE-2018-8828Kamailio out-of-bounds write vulnerabilityA Buffer Overflow issue was discovered in Kamailio before 4.4.7, 5.0.x before 5.0.6, and 5.1.x before 5.1.2. A specially crafted REGISTER message wit…EPSS 30%9.8CVE-2013-7426Kamailio unrestricted file upload vulnerabilityInsecure Temporary file vulnerability in /tmp/kamailio_fifo in kamailio 4.0.1.EPSS 2.2%9.8CVE-2016-2385Debian linux memory buffer overflow vulnerabilityHeap-based buffer overflow in the encode_msg function in encode_msg.c in the SEAS module in Kamailio (formerly OpenSER and SER) before 4.3.5 allows r…EPSS 31%7.8CVE-2015-1590Kamailio permissions and access controls vulnerabilityThe kamcmd administrative utility and default configuration in kamailio before 4.3.0 use /tmp/kamailio_ctl.EPSS 0.43%7.8CVE-2015-1591Kamailio permissions and access controls vulnerabilityThe kamailio build in kamailio before 4.2.0-2 process allows local users to gain privileges.EPSS 0.39%

Source: NIST National Vulnerability Database (record CVE-2026-39863), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.