External risk intelligence

Juniper Junos OS MX Series Stack Buffer Overflow Remote Code Execution

CVE advisorySeverity: CRITICAL (CVSS 9.3)

CVE-2026-102182

The vulnerability affects the kmd component of Juniper Networks Junos OS, which handles IKE (Internet Key Exchange) for VPN and IPsec tunnels. These services are designed to be internet-facing to facilitate remote connectivity and branch office communication, making them public-facing by design and reachable to unauthenticated network attackers.

Buffer Overflow

Halo Surface Signal: 5 out of 5 — more likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A critical vulnerability has been identified in Juniper Networks Junos OS on MX Series devices. This issue, specifically a stack-based buffer overflow, could allow an unauthenticated attacker to execute code with root privileges through crafted network packets. This capability means the system's core security functions could be compromised remotely.

A code execution flaw exists in network security software.
It impacts internet-facing network devices.
Confirm exposure to prioritize potential impact.

Attack Path

How an attacker could exploit the issue

An unauthenticated attacker can target the Juniper Networks Junos OS on MX Series by sending specially crafted IKE certificate-based packets over the network. This interaction involves the kmd component, leading to a stack-based buffer overflow. Successful exploitation allows the attacker to execute arbitrary code with root privileges.

No authentication or user interaction needed.
Triggered by specific IKE certificate packets.
Risk of unauthenticated root code execution.

Live Threat

Current exploitation, exposure, and threat context

A stack-based buffer overflow in Juniper Networks Junos OS's kmd component could allow an unauthenticated network attacker to execute code as root. This could occur when the system processes specific IKE certificate-based packets, potentially affecting the integrity and availability of the device.

System integrity and code execution.
Unauthenticated network packets processed.
Device compromise and unauthorized control.

Operational Fix

Recommended remediation, mitigation, and detection steps

The network security and infrastructure teams are likely responsible for addressing this vulnerability in Juniper Networks Junos OS on MX Series devices. The initial focus should be on identifying all instances of the affected Junos OS, assessing their exposure and business criticality, and then coordinating remediation efforts with the accountable system owners.

Network and infrastructure teams own the issue.
Verify external reachability and criticality first.
Plan remediation based on risk and vendor coordination.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is the kmd component in Junos OS on MX Series?

The kmd component serves as the key management daemon within Juniper Networks Junos OS. It is responsible for handling the Internet Key Exchange (IKE) protocol, which is essential for establishing secure VPN tunnels and encrypted IPsec communications between network sites or remote users.

How does a stack-based buffer overflow lead to root execution in CVE-2026-102182?

This vulnerability, classified as CWE-121, occurs when the software writes more data to a memory buffer on the stack than it can hold. By sending a specially crafted packet, an attacker can overwrite adjacent memory, allowing them to redirect the program's execution flow and run unauthorized commands with the highest level of system permissions (root).

Do I need to be authenticated to trigger this buffer overflow?

No. The vulnerability does not require authentication or any form of user interaction. However, the flaw is only triggered when the system specifically processes malformed IKE certificate-based packets. Standard, valid network traffic that does not utilize these specific certificate structures will not trigger the memory overflow.

Is my device at risk if it is not internet-facing?

Halo Surface Signal notes that because kmd manages VPN and IPsec tunnels, these devices are often intentionally placed on the internet to support remote connections. If your MX Series device is shielded from the public internet, the practical risk is reduced; however, it remains vulnerable to any attacker who has gained a foothold within your internal network.

When should I prioritize patching for this vulnerability?

You should prioritize patching by first identifying all MX Series devices running the affected Junos OS versions. Focus on systems that handle critical infrastructure or are reachable via public networks, then coordinate with your network administrators to schedule maintenance windows for applying the vendor-provided software updates.

References

supportportal.juniper.net/JSA112196

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.