Cyber Resilience

CVE-2026-39864

Medium

Published: 08 April 2026

Published
08 April 2026
Modified
15 April 2026
KEV Added
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Patch
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CVSS Score v3.1 4.4 CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0023 46.5th percentile
Risk Priority 9 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-39864 is a medium-severity Out-of-bounds Read (CWE-125) vulnerability in Kamailio Kamailio. Its CVSS base score is 4.4 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 46.5th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

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)…

more

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.

CWE(s)
CWE-125

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1499.004 Application or System Exploitation Impact
Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.
attack.mitre.org →
Why these techniques?

Remote exploitation of public-facing SIP server via crafted packet directly enables T1190; resulting process crash matches T1499.004 Application or System Exploitation for DoS.

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

Affected Assets

kamailio
kamailio
≤ 5.8.7 · 6.0.0 — 6.0.5

Mitigating Controls

No mitigating controls mapped yet. The per-CVE control annotator has not reached this CVE.

References