CVE-2026-101971 in Junos OS
Summary
by MITRE • 10/14/2026
An Allocation of Resources Without Limits or Throttling vulnerability in rpd, the routing protocol daemon, of Juniper Networks Junos OS and Junos OS Evolved platforms allows an unauthenticated adjacent attacker to cause a denial of service and heap memory corruption via OSPFv3 messages on an enabled broadcast interface.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 10/14/2026
The identified vulnerability represents a critical flaw within rpd, the routing protocol daemon responsible for managing dynamic routing protocols in Juniper Networks Junos OS and Junos OS Evolved platforms. This specific issue is classified as an Allocation of Resources Without Limits or Throttling, which corresponds to CWE-770 under the Common Weakness Enumeration standard. The core technical deficiency lies in the handling of OSPFv3 (Open Shortest Path First version 3) messages on broadcast interfaces that have routing protocols enabled. Specifically, the daemon fails to enforce adequate resource limits or throttling mechanisms when processing incoming OSPFv3 packets from adjacent neighbors. This lack of input validation and rate limiting allows an attacker to exploit the system by sending a high volume of specially crafted OSPFv3 messages without restriction.
An unauthenticated attacker positioned on the same local network segment can leverage this vulnerability to trigger severe operational disruptions. By flooding the target device with excessive or malformed OSPFv3 packets, the attacker forces rpd to allocate memory resources beyond its intended capacity. This unchecked allocation leads directly to heap memory corruption within the daemon process. The immediate consequence of such resource exhaustion and memory corruption is a denial of service condition. Depending on the severity of the memory corruption and the stability of the underlying operating system kernel, this can result in the crash or restart of the routing protocol daemon itself. In more severe scenarios involving critical memory structures, it may lead to a complete system reboot or instability affecting other network services running on the device.
The operational impact is significant for any organization relying on Juniper infrastructure for core or distribution layer networking. A denial of service in this context disrupts dynamic route learning and maintenance, potentially causing routing loops, black holes, or total loss of connectivity to adjacent networks that depend on OSPFv3 for path calculation. Furthermore, the potential for heap memory corruption introduces a secondary risk vector where unstable memory states could theoretically be exploited further by sophisticated attackers to achieve arbitrary code execution, although the primary reported impact remains denial of service and system instability. This vulnerability highlights the importance of securing routing protocol interfaces against untrusted adjacent hosts, as traditional perimeter defenses often do not inspect traffic between devices on the same broadcast domain.
Mitigation strategies should focus on both immediate operational controls and long-term architectural improvements. The most effective remediation is to apply the vendor-provided software patches that address this specific flaw in rpd. Administrators must ensure their Junos OS or Junos OS Evolved installations are updated to versions where these resource limits have been properly enforced. In environments where patching cannot be immediately implemented, network segmentation and access control lists should be deployed to restrict OSPFv3 traffic only from trusted adjacent neighbors. Implementing rate limiting on routing protocol interfaces can also help mitigate the impact of such floods by dropping excessive packets before they trigger memory exhaustion. Additionally, enabling logging for routing protocol events allows security teams to detect anomalous spikes in OSPFv3 message rates that may indicate an ongoing exploitation attempt. This vulnerability aligns with MITRE ATT&CK techniques related to resource hijacking and denial of service via network layer protocols, emphasizing the need for robust input validation and resource management in critical infrastructure components.