CVE-2026-102084: CWE-1286 Improper Validation of Syntactic Correctness of Input in Juniper Networks Junos OS

This vulnerability (CWE-1286) in Juniper Networks Junos OS SRX Series VPN daemon arises from improper validation of syntactic correctness of input messages related to AutoDiscovery VPN (ADVPN). When a device receives a message containing one or more specifically malformed attributes from a peer, a buffer overflow occurs, enabling remote code execution. Exploitation requires the attacker to be authenticated as a peer by possessing the shared secret or compromising an existing peer, making the attack difficult but potentially devastating. Affected versions include all releases before 23.2R2-S7.7, versions from 23.4 up to but excluding 23.4R2-S7, from 24.2 up to but excluding 24.2R2-S4, from 24.4 up to but excluding 24.4R2-S3, from 25.2 up to but excluding 25.2R2, and from 25.4 up to but excluding 25.4R1-S3.

An attacker who can send specially crafted malformed ADVPN messages to a Junos OS SRX device and who has the shared secret or can impersonate a peer can trigger a buffer overflow leading to remote code execution. This allows the attacker to gain complete control over the affected device, impacting confidentiality, integrity, and availability.

A patch is available for this vulnerability. Users should upgrade to the fixed versions: 23.2R2-S7.7 or later, 23.4R2-S7 or later, 24.2R2-S4 or later, 24.4R2-S3 or later, 25.2R2 or later, and 25.4R1-S3 or later. Since this is a cloud-managed service, Juniper manages remediation for cloud-hosted instances. Check the official Juniper advisory for the latest patch and mitigation guidance.