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How CVE-2026-33771 Works
CVE-2026-33771 is a Weak Password Requirements vulnerability (CWE-521) affecting Juniper Networks CTP OS versions 9.2R1 and 9.2R2. The flaw resides in the password management function of the operating system. While the administrative console provides a menu that allows administrators to configure password complexity requirements—such as minimum length, character diversity, or expiration policies—these configured settings are never actually saved to the system’s active configuration.
When an administrator uses the menu to set password policies, the interface acknowledges the input and may even display the intended requirements. However, due to a logic flaw in the configuration persistence mechanism, the system discards these settings upon exit or reboot. The issue can be verified using the menu option “Show password requirements”, which will display the settings that were supposedly applied—yet the system continues to operate without enforcing any of them.
This means that local user accounts—including administrative accounts—can be created or modified with passwords that do not meet any strength criteria. The system accepts passwords of arbitrary simplicity, including common dictionary words, short strings, or predictable patterns. An unauthenticated, network-based attacker who can reach the device over the network (typically via SSH or console ports) can then attempt to guess these weak passwords. Because no authentication is required to initiate the guessing attack (only to complete it successfully), the attack surface is wide open.
The vulnerability is particularly dangerous because CTP OS devices are often deployed in edge networking environments, such as circuit-to-packet aggregation points, where they may be reachable from untrusted networks. A successful compromise grants the attacker full administrative control over the device, enabling them to modify configurations, intercept traffic, pivot to internal networks, or completely disable the device. The vendor has assigned a CVSS v4.0 score of 9.1 (Critical) and a CVSS v3.1 score of 7.4 (High) to this vulnerability.
DailyCVE Form:
Platform: Juniper CTP OS
Version: 9.2R1, 9.2R2
Vulnerability: Weak Password Requirements (CWE-521)
Severity: Critical (CVSS v4.0: 9.1)
Date: 2026-04-09
Prediction: 2026-04-15 (vendor patch 9.3R1 available)
What Undercode Say:
Check CTP OS version show version Verify if password requirements are actually enforced show password requirements Attempt to set a weak password for a local account set system login user admin password "password123" Check if the weak password is accepted (vulnerable if accepted) Expected behavior: should reject weak passwords Verify running configuration for password policy settings show configuration system login Check if any password complexity parameters are present show configuration | match password Manual inspection of configuration file cat /config/juniper.conf.gz | zcat | grep -i password
Analytics Insight:
- CVE ID: CVE-2026-33771
- CWE: CWE-521 – Weak Password Requirements
- CVSS v3.1: 7.4 (High)
- CVSS v4.0: 9.1 (Critical)
- EPSS: < 1% (Very Low)
- CISA KEV: Not listed
- SSVC: Exploitation: none | Automatable: no | Technical Impact: total
- Exploit Price (est.): USD $5k–$25k
- Exploit Availability: No public exploit available
- Attack Vector: Remote, Unauthenticated
- Affected Products: Juniper CTP OS 9.2R1 and 9.2R2
- Fixed Releases: 9.3R1 and all subsequent releases
Exploit:
An attacker can exploit CVE-2026-33771 through the following approach:
1. Reconnaissance: Identify Juniper CTP OS devices running versions 9.2R1 or 9.2R2 by scanning for open SSH ports (default port 22) or console access points.
2. Password Guessing: Because the system does not enforce any password complexity requirements, local accounts may have weak passwords such as admin, password123, juniper, 123456, or the device’s serial number.
3. Brute-Force Attack: An unauthenticated attacker can launch dictionary or brute-force attacks against the SSH or console login interface without triggering any password policy violations (since no lockout or complexity rules are enforced).
4. Full Compromise: Upon successful credential guessing, the attacker gains administrative access to the device, allowing them to:
– Modify or delete device configurations
– Intercept or manipulate network traffic
– Use the device as a pivot point for lateral movement
– Install backdoors or malware
– Completely disable the device (denial of service)
Example: Hydra brute-force against CTP OS SSH hydra -l admin -P /usr/share/wordlists/rockyou.txt ssh://<target-ip> Example: Manual login attempt with common credentials ssh admin@<target-ip> Password: admin Password: password123 Password: juniper
Protection:
- Immediate Upgrade: Upgrade Juniper CTP OS to version 9.3R1 or newer, which contains the official vendor patch that correctly saves and enforces password complexity requirements.
- Access Control Lists (ACLs): Restrict CLI access to only trusted hosts and administrators by configuring firewall filters or access lists:
set firewall filter restrict-ssh term trusted from source-address <trusted-ip>/32 set firewall filter restrict-ssh term trusted then accept set firewall filter restrict-ssh term default then discard set interfaces <interface> unit 0 family inet filter input restrict-ssh
- Manual Password Enforcement: Until the patch can be applied, manually enforce strong password policies during user creation and conduct regular password audits:
– Require minimum 12 characters
– Require uppercase, lowercase, numbers, and special characters
– Enforce regular password rotation
– Disable default or unused accounts
4. Network Segmentation: Place CTP OS devices behind firewalls or VPN gateways to minimize exposure to untrusted networks.
5. Monitoring and Logging: Enable detailed logging of login attempts and monitor for unusual authentication patterns:
set system syslog file auth-log authorization any set system syslog file auth-log info show log auth-log | match "Failed password"
6. Vendor Workaround: Use access lists to limit SSH and console access exclusively to trusted management networks until the upgrade can be performed.
Impact:
Confidentiality: An attacker who successfully guesses a weak administrative password gains full read access to device configurations, network topology information, and potentially sensitive data traversing the device.
Integrity: With administrative control, the attacker can modify system configurations, routing tables, firewall rules, and ACLs. They can also inject malicious configurations, redirect traffic, or install unauthorized software.
Availability: The attacker can completely disable the device by altering critical configurations, initiating reboots, or performing destructive operations. This can lead to prolonged network outages.
Lateral Movement: Compromised CTP OS devices often serve as aggregation points in service provider or enterprise networks. An attacker can use the device as a pivot to attack internal network segments, other network devices, or backend systems.
Compliance and Regulatory: Organizations subject to regulations such as PCI-DSS, HIPAA, or NIST 800-53 may face compliance violations if weak password policies are not enforced, potentially leading to fines or legal consequences.
Operational Disruption: Recovery from a successful compromise requires forensic investigation, device re-imaging, configuration restoration, and potentially network-wide password resets—all of which incur significant operational costs and downtime.
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Sources:
Reported By: nvd.nist.gov
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