Description

A Heap-based Buffer Overflow vulnerability in the sdxd service-deployment daemon of Juniper Networks Junos OS and Junos OS Evolved allows a remote unauthenticated attacker who can control or intercept the configured SDX/SRC server connection to execute code as root or cause denial of service via a crafted frame received over the service-deployment TCP connection.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "9.8",
  "pubDate": "2026-10-14T17:18:05.147Z",
  "pubdate": "2026-10-14T17:18:05.147Z",
  "executiveSummary": "A critical heap-based buffer overflow vulnerability exists within the sdxd service-deployment daemon of Juniper Networks Junos OS and Junos OS Evolved. This flaw allows a remote, unauthenticated attacker to achieve arbitrary code execution with root privileges or induce a denial-of-service (DoS) condition. The vulnerability resides in the handling of communication over the service-deployment TCP connection. Exploitation requires the attacker to possess the capability to control or intercept the configured SDX/SRC server connection. Given the elevated privilege level (root) and the remote, unauthenticated nature of the attack, this vulnerability represents a severe security risk, potentially allowing for full system compromise or service disruption if an attacker can successfully manipulate the traffic stream between the device and the service-deployment server.",
  "technicalDetails": "The vulnerability is localized to the sdxd (service-deployment daemon) process in Junos OS and Junos OS Evolved. The root cause is an improper memory management implementation during the processing of frames received over the service-deployment TCP protocol. Specifically, the daemon fails to adequately validate the bounds of incoming data before copying it into a heap-allocated buffer. When a crafted, malicious frame is transmitted over the established connection, it triggers a heap-based buffer overflow condition.\nThe exploitation flow begins with a remote, unauthenticated attacker positioning themselves to intercept or control the communication channel established between the Junos device and its designated SDX/SRC server. Because the protocol handling within sdxd lacks sufficient input sanitization, the attacker can inject a payload exceeding the allocated heap buffer size. By crafting the frame structure to overwrite adjacent heap metadata or function pointers, the attacker can redirect the execution flow of the sdxd process.\nGiven that the sdxd service operates with root privileges, successful exploitation leads directly to arbitrary code execution at the highest system privilege level. Alternatively, if the heap corruption results in a memory access violation (e.g., attempting to reference unmapped memory or causing a heap consistency failure), the daemon will crash, leading to a permanent denial-of-service state for the service-deployment functionality. The lack of authentication requirements for the TCP connection ensures that any entity capable of performing a Man-in-the-Middle (MitM) attack or spoofing the expected server response can initiate the exploitation sequence. The technical complexity involves bypassing any underlying heap protections, such as ASLR or heap cookies, if implemented, though the fundamental flaw remains an unchecked memory copy operation within the daemon's packet handling logic.\nThe impact post-exploitation is critical, as it grants the attacker complete control over the affected device, allowing for persistent access, modification of configuration, or lateral movement within the network. Mitigation requires rigorous control over the communication path and adherence to the principle of least privilege regarding daemon operation."
}