# CVE-2026-21915: JSI Virtual Lightweight Collector: Shell escape allows privilege escalation to root

> A local high-privileged attacker can inject shell commands via the CLI to escalate privileges to root on Juniper JSI vLWC.

- **Severity:** High 8.4 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/R:U/RE:M`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 9 Apr 2026
- **Updated:** 13 Apr 2026
- **Also known as:** GHSA-r893-59mm-pxrg

## What is CVE-2026-21915?

CVE-2026-21915 is a high-severity command injection vulnerability in Juniper Networks JSI LWC, published on 9 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A Permissive List of Allowed Input vulnerability in the CLI of Juniper Networks Support Insights (JSI) Virtual Lightweight Collector (vLWC) allows a local, high privileged attacker to escalate their privileges to root.

The CLI menu accepts input without carefully validating it, which allows for shell command injection. These shell commands are executed with root permissions and can be used to gain complete control of the system.

This issue affects all JSI vLWC versions before 3.0.94.

Weakness: CWE-78 (Improper Neutralization of Special Elements used in an OS Command), CWE-183 (Permissive List of Allowed Inputs)

## Which versions are affected by CVE-2026-21915?

It affects 1 product.


Products: Juniper Virtual Lightweight Collector.

## How do I fix CVE-2026-21915?

No fix has been published for CVE-2026-21915 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-21915 being exploited?

There is no known exploitation of CVE-2026-21915 in the wild and no public exploit code.

## Other vulnerabilities in Juniper Networks JSI LWC

- [CVE-2026-33784](https://insights.sbomify.com/CVE-2026-33784/): Hardcoded credentials in JSI LWC (critical 9.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-21915 and fix it if it is affected.

What it is: CVE-2026-21915 is a high-severity command injection vulnerability in Juniper Networks JSI LWC, published on 9 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-21915 in the wild and no public exploit code.

Affected product: Juniper Networks JSI LWC. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-21915/ (Markdown: https://insights.sbomify.com/CVE-2026-21915/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-21915
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-21915
- OSV: https://osv.dev/vulnerability/CVE-2026-21915

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-21915/
Summaries are generated and may contain mistakes; the official description above is the record.