Is CVE-2026-21915 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-21915 being exploited in the wild.

How severe is CVE-2026-21915?

Medium severity, with a CVSS score of 6.7, published 9 April 2026.

Is there a fix for CVE-2026-21915?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-21915 attacked?

It is attacked with local access, in a network appliance.

Am I affected by CVE-2026-21915?

Check whether you run Juniper Virtual Lightweight Collector or Juniper Networks Support Insights Virtual Lightweight Collector. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-21915: Juniper Networks JSI vLWC privilege escalation in CLI

CVE-2026-21915 · Severity: medium · CVSS 6.7 · Published 2026-04-09

A security vulnerability exists in Juniper Networks Support Insights (JSI) Virtual Lightweight Collector, a tool used for network monitoring and data collection. A local attacker with high-level administrative access can bypass security restrictions to gain full root control over the system. This could allow an attacker to completely compromise the device, potentially leading to data theft or disruption of network monitoring operations.

Vendors: Juniper, Juniper Networks.

Quick answers

Is CVE-2026-21915 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-21915 being exploited in the wild.
How severe is CVE-2026-21915?: Medium severity, with a CVSS score of 6.7, published 9 April 2026.
Which products and versions are affected?: Juniper Networks Support Insights (JSI) Virtual Lightweight Collector (vLWC) All versions before 3.0.94.
Is there a fix for CVE-2026-21915?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-21915 attacked?: It is attacked with local access, in a network appliance.
Am I affected by CVE-2026-21915?: Check whether you run Juniper Virtual Lightweight Collector or Juniper Networks Support Insights Virtual Lightweight Collector. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A Permissive List of Allowed Input vulnerability (CWE-183) exists in the Command Line Interface (CLI) of Juniper Networks Support Insights (JSI) Virtual Lightweight Collector (vLWC). The CLI menu fails to properly validate user input, leading to an OS command injection vulnerability (CWE-78). A local attacker who already possesses high-privileged access can exploit this flaw to execute shell commands with root permissions. Successful exploitation results in complete system compromise. The issue is resolved in version 3.0.94 and all subsequent releases.

Affected products

Juniper Networks Support Insights (JSI) Virtual Lightweight Collector (vLWC) All versions before 3.0.94

Timeline

2026-04-09: advisory: Initial advisory published by Juniper Networks
2026-04-09: disclosed

References

https://kb.juniper.net/JSA106016

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