CVE-2026-102014 in Junos OS
Summary
by MITRE • 10/14/2026
A Stack-based Buffer Overflow vulnerability in the authd process of Juniper Networks Junos OS allows an attacker able to influence a configured RADIUS server to cause authd to crash or execute code with root privileges via a malicious RADIUS response.
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Analysis
by VulDB Data Team • 10/14/2026
The identified vulnerability represents a critical security flaw within the authentication daemon, known as authd, which is a core component of Juniper Networks Junos OS responsible for handling network access control and user authentication processes. This specific weakness is classified as a stack-based buffer overflow, a type of memory corruption error that occurs when a program writes more data to a fixed-length block of memory on the call stack than it can hold. In this context, the vulnerability arises from insufficient bounds checking during the processing of Remote Authentication Dial-In User Service responses. An attacker who has the ability to influence or control the configuration of a RADIUS server used by the Junos device can exploit this flaw by sending specially crafted, oversized packets that exceed the allocated buffer space within the authd process.
The technical mechanism behind this exploitation involves overwriting adjacent memory locations on the stack, including critical return addresses and saved frame pointers. By carefully crafting the malicious payload contained within the RADIUS response, an attacker can manipulate these overwritten values to redirect the execution flow of the program. This manipulation allows for two primary outcomes: a denial-of-service condition where the authd process crashes due to invalid memory access, or, more severely, arbitrary code execution with root privileges. Since authd operates at a high privilege level within the operating system hierarchy, gaining control over its execution path effectively grants the attacker full administrative control over the network device. This capability enables the compromise of the entire infrastructure protected by the Juniper device, including potential lateral movement to other systems on the internal network and exfiltration of sensitive data.
From a threat intelligence perspective, this vulnerability aligns with Common Weakness Enumeration identifier CWE-120, which describes buffer copy without checking size limits, specifically in stack-based scenarios. The exploitation technique maps directly to MITRE ATT&CK techniques related to privilege escalation and process injection, such as T1068 Exploitation for Privilege Escalation or potentially T1543 Create or Modify System Process depending on the specific payload delivered. The attack vector is classified as network-based but requires a degree of configuration influence, meaning it may be categorized under Local Network attacks if the attacker has prior access to modify RADIUS server configurations within the trusted zone. This highlights the importance of strict input validation and secure coding practices in all components that handle external authentication protocols.
The operational impact of this vulnerability is severe due to its potential for complete system compromise without requiring physical access or complex social engineering tactics beyond initial network reachability to the affected device's management interface or RADIUS configuration endpoints. Once exploited, an attacker can bypass standard security controls, install persistent backdoors, and disrupt critical authentication services, leading to significant downtime and data integrity issues. Mitigation strategies must prioritize immediate application of vendor-provided patches that address the buffer handling logic within authd. In environments where patching is not immediately feasible, network segmentation should be enforced to restrict access to RADIUS servers from untrusted networks, and strict input validation rules should be implemented at any intermediate security devices such as firewalls or intrusion prevention systems to drop packets with anomalous sizes before they reach the Junos device. Regular auditing of authentication configurations and monitoring for unusual authd process behavior can also aid in early detection and response efforts.