CVE-2026-103994

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Heap-based Buffer Overflow in Juniper Networks Junos OS VXLAN Gateway Daemon

Publication date: 2026-10-14

Last updated on: 2026-10-15

Assigner: Juniper Networks, Inc.

Description

A Heap-based Buffer Overflow vulnerability in the VXLAN Gateway Daemon (vgd) of Juniper Networks Junos OS allows a malicious or compromised SDN-controller to cause a complete outage of the OVSDB control plane and possibly remote code execution.

CVSS Scores

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Meta Information

Published

2026-10-14

Last Modified

2026-10-15

Generated

2026-10-19

AI Q&A

2026-10-15

EPSS Evaluated

2026-10-18

NVD

CVE-2026-103994

EUVD

EUVD-2026-101434

Affected Vendors & Products

Vendor	Product	Version / Range
Juniper	Networks	Junos OS 0
Juniper	Networks	Junos OS 23.4
Juniper	Networks	Junos OS 24.2
Juniper	Networks	Junos OS 24.4
Juniper	Networks	Junos OS 25.2
Juniper	Networks	Junos OS 25.4
Juniper	Networks	Junos OS 26.2

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-122	A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

Attack-Flow Graph

Executive Summary

This is a Heap-based Buffer Overflow vulnerability in Juniper Networks Junos OS's VXLAN Gateway Daemon (vgd). It allows a malicious or compromised SDN-controller to crash the OVSDB control plane and potentially execute arbitrary code remotely.

Detection Guidance

Detection requires monitoring for unexpected behavior in the VXLAN Gateway Daemon (vgd) or OVSDB control plane. Check for crashes, high CPU usage, or memory corruption in vgd processes. Juniper recommends inspecting logs for vgd-related errors or anomalies in SDN-controller communications.

Impact Analysis

An attacker could exploit this to cause a complete outage of the OVSDB control plane, disrupting network operations. In severe cases, it may lead to remote code execution, allowing full system compromise.

Compliance Impact

This vulnerability could lead to unauthorized access or control plane outages, potentially compromising data confidentiality and integrity. Such impacts may violate compliance requirements under GDPR (data protection) and HIPAA (health data security) by exposing sensitive information or disrupting critical systems.

Mitigation Strategies

Apply the latest Junos OS security patches from Juniper Networks to address the heap-based buffer overflow in the VXLAN Gateway Daemon. Isolate affected systems from untrusted networks and monitor for unusual activity in the OVSDB control plane.

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