CVE-2026-21915

Q: How do I fix CVE-2026-21915?

Upgrade virtual lightweight collector to 3.0.94 or later.

Q: Is CVE-2026-21915 being actively exploited?

Not that we know of. CVE-2026-21915 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 2.2% is the estimated probability that it will be exploited in the next 30 days. That is higher than 81% of all scored CVEs.

Q: How severe is CVE-2026-21915?

CVE-2026-21915 has a CVSS v3 base score of 6.7, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

Q: What does CVE-2026-21915 affect?

Published advisories record a fix for virtual lightweight collector (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

MEDIUMEPSS 81th pctl

6.7

CVSS v3

NVD

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.

CWE-183 CWE-78OS Command Injection

How to fix

Remediation Available

virtual lightweight collectorNVD

Affected:< 3.0.94Fixed in:3.0.94CVE-2026-21915derived from NVD

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorLocal

Attack ComplexityLow

Privileges RequiredHigh

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Exploit Intelligence

2.24%probability of exploitation in 30 days

81stpercentile

Elevated risk: more likely to be exploited than 81% of all known CVEs.

References

Vendor Advisory1

kb.juniper.net

Related Vulnerabilities

Other CWE-183 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2020-25696	High	7.5	2.6%	-	Fix
CVE-2020-1694	Medium	4.9	1.6%	-	Fix
CVE-2024-1654	High	7.2	1.3%	-	Fix
CVE-2023-4399	Medium	6.6	1.1%	-	Fix
CVE-2021-34787	Medium	5.3	1.0%	-	Fix
CVE-2021-40128	Medium	5.3	1.0%	-	-

Common questions

How do I fix CVE-2026-21915?

Upgrade virtual lightweight collector to 3.0.94 or later.

Is CVE-2026-21915 being actively exploited?

Not that we know of. CVE-2026-21915 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 2.2% is the estimated probability that it will be exploited in the next 30 days. That is higher than 81% of all scored CVEs.

How severe is CVE-2026-21915?

CVE-2026-21915 has a CVSS v3 base score of 6.7, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2026-21915 affect?

Published advisories record a fix for virtual lightweight collector (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-07-08.