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Vulnerabilities

Vulnerability · CVE-2026-39863

Kamailio is an open source implementation of a SIP Signaling Server.

Published Apr 8, 2026 · catalog updated Jul 24, 2026 · Kamailio is an open

Check if you run it

No confirmed exploitation is on record for CVE-2026-39863. EPSS is 0.55%. Act only if a listed version of Kamailio is an open is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Kamailio is an open).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.55%
Remediation
Advisory link
Affected products
cpe 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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe kamailio/kamailio6.1.0

How to fix CVE-2026-39863

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-39863. EPSS is 0.55%. Act only if a listed version of Kamailio is an open is installed.

Which versions are affected?

Compare what you have installed with 6.1.0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-119: Buffer Overflow. EPSS 0.55%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Apr 8, 2026 · NIST NVD

    Detected

    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

  2. Jul 24, 2026 · NIST NVD

    Updated

    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

Sources

  • CVE.orgVulnerability recordCVE-2026-39863

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-39863

    30-day exploitation probability 0.5%

    first.org
  • NIST NVDVulnerability recordCVE-2026-39863

    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 pack

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.