CVE-2025-59975: Juniper Junos Space DoS Vulnerability

CVE-2025-59975 Overview

An Uncontrolled Resource Consumption vulnerability exists in the HTTP daemon (httpd) of Juniper Networks Junos Space that allows an unauthenticated network-based attacker to flood the device with inbound API calls, consuming all system resources and leading to a Denial of Service (DoS) condition.

After continuously flooding the system with inbound connection requests, all available file handles become consumed, blocking access to the system via SSH and the web user interface (WebUI), resulting in a complete management interface DoS. A manual reboot of the system is required to restore functionality.

Critical Impact

Unauthenticated attackers can completely disable management access to Junos Space devices, requiring manual system reboot to restore operations. This impacts network management capabilities and can disrupt enterprise infrastructure administration.

Affected Products

• Juniper Junos Space all versions before 22.2R1 Patch V3
• Juniper Junos Space from 23.1 before 23.1R1 Patch V3
• All Junos Space deployments with network-exposed HTTP daemon

Discovery Timeline

• 2025-10-09 - CVE-2025-59975 published to NVD
• 2026-01-23 - Last updated in NVD database

Technical Details for CVE-2025-59975

Vulnerability Analysis

This vulnerability is classified as CWE-400 (Uncontrolled Resource Consumption). The HTTP daemon in Junos Space fails to properly limit the rate and volume of incoming API connection requests, allowing an attacker to exhaust system file handles through sustained flooding attacks.

The vulnerability is exploitable over the network without authentication, meaning any attacker with network access to the Junos Space management interface can initiate an attack. The impact is limited to availability - there is no compromise of data confidentiality or integrity, but the complete loss of management access severely impacts operational capabilities.

When the attack succeeds, the system becomes unresponsive to both SSH and WebUI connections, effectively locking out administrators from the management platform. This creates a significant operational risk, particularly in enterprise environments where Junos Space serves as a centralized network management solution.

Root Cause

The root cause lies in insufficient resource management within the HTTP daemon component. The httpd service does not implement adequate rate limiting or connection throttling mechanisms for incoming API requests. This allows an attacker to rapidly open numerous connections, each consuming a file handle, until the system's file descriptor limit is exhausted.

Without proper safeguards such as connection limits per source IP, request rate limiting, or dynamic resource allocation, the daemon allows unbounded resource consumption from unauthenticated sources.

Attack Vector

The attack is conducted over the network targeting the HTTP daemon service. An attacker floods the Junos Space system with a high volume of API connection requests in rapid succession. As each connection consumes system file handles, the available pool is depleted until no resources remain for legitimate administrative connections.

The attack does not require authentication or valid credentials - any network actor capable of reaching the management interface can execute this attack. The sustained nature of the attack prevents the system from recovering on its own, necessitating administrator intervention through a manual reboot.

Detection Methods for CVE-2025-59975

Indicators of Compromise

• Sudden inability to connect to Junos Space via SSH or WebUI
• Abnormally high number of concurrent HTTP connections from single or multiple sources
• System logs indicating file handle exhaustion or resource limit errors
• Elevated CPU or memory utilization on the Junos Space appliance preceding service unavailability

Detection Strategies

• Monitor connection rates to the HTTP daemon and alert on anomalous spikes in API requests
• Implement network-based intrusion detection rules to identify HTTP flood patterns targeting Junos Space
• Configure alerting for file descriptor usage approaching system limits
• Deploy log analysis to correlate httpd connection logs with availability incidents

Monitoring Recommendations

• Establish baseline metrics for normal API traffic volume to Junos Space
• Configure SNMP or syslog monitoring for resource exhaustion warnings
• Implement network flow analysis to detect sustained high-volume traffic to management ports
• Set up automated health checks for Junos Space management interfaces to detect availability loss

How to Mitigate CVE-2025-59975

Immediate Actions Required

• Restrict network access to Junos Space management interfaces using firewall rules or ACLs
• Implement rate limiting at the network perimeter for traffic destined to Junos Space
• Ensure Junos Space is not exposed to untrusted networks or the internet
• Plan for emergency patching during the next available maintenance window

Patch Information

Juniper Networks has released patches to address this vulnerability. Organizations should upgrade to the following versions:

• Junos Space 22.2R1 Patch V3 or later for versions prior to 22.2R1 Patch V3
• Junos Space 23.1R1 Patch V3 or later for versions in the 23.1 release train

Refer to the Juniper Security Advisory JSA103172 for detailed upgrade instructions and patch availability.

Workarounds

• Deploy network-level rate limiting to throttle incoming connections to the HTTP daemon
• Configure firewall rules to restrict management interface access to trusted administrative subnets only
• Implement connection limits per source IP at the load balancer or network layer
• Consider deploying a reverse proxy with DDoS protection capabilities in front of Junos Space

# Example firewall rule to restrict Junos Space management access (iptables)
# Allow management access only from trusted admin subnet
iptables -A INPUT -p tcp --dport 443 -s 10.10.10.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP

# Rate limit connections to management interface
iptables -A INPUT -p tcp --dport 443 -m connlimit --connlimit-above 50 -j DROP