Juniper Junos OS CVE-2026-102047

Exploitation requires that MVRP (Multiple VLAN Registration Protocol) is explicitly enabled on at least one interface - this is a non-default Layer 2 feature, so devices without MVRP configured are not exposed. The attacker must also have Layer 2 adjacency (AV:A): direct access to the same broadcast domain/VLAN as the MVRP-enabled interface, meaning the frame cannot be routed across Layer 3 boundaries or exploited remotely over the Internet. No authentication is required (PR:N) and no user interaction (UI:N). The combination of mandatory MVRP configuration plus adjacency is the primary factor limiting real-world exploitability; impact is confined to availability of Layer 2 control protocols on the affected device (VC/VI:N).

This is a genuine but bounded operational risk rather than a top-tier emergency. The only provided scoring is a CVSS 4.0 vector (7.1) with AV:A (adjacent/Layer 2), AC:L, AT:N, PR:N, UI:N and impact limited to availability (VA:H, with subsequent-system SA:L and VC/VI/VA confidentiality/integrity all N) - consistent with the description of a denial of service in Layer 2 control protocols, not code execution or data exposure. The adjacency requirement (AV:A) is the single most important limiting signal: an attacker must already be on the same Layer 2 segment/broadcast domain as an MVRP-enabled interface, which excludes remote Internet-based exploitation and sharply narrows the threat population to insiders, compromised adjacent devices, or attackers with physical/VLAN access. No EPSS score, KEV listing, or POC was provided in the input, so exploitation probability cannot be quantified from this data; absence of KEV/POC is not proof of safety but indicates no confirmed active exploitation or public exploit at analysis time. There is no conflicting data between the vector and description - both agree on adjacent, unauthenticated, availability-only impact. Net: a credible DoS against network infrastructure that should be patched on a normal maintenance cadence, prioritized higher only where MVRP is actually enabled on exposed/untrusted Layer 2 segments.

An attacker with Layer 2 adjacency to a Junos or Junos OS Evolved device (e.g., a rogue or compromised host on the same VLAN/broadcast domain) sends a crafted MVRP Ethernet frame to an MVRP-enabled interface. The malformed frame triggers an input-consistency validation flaw in the l2cpd process, disrupting associated Layer 2 control protocols and causing a denial of service. No public exploit code was identified in the provided data, and no authentication or user interaction is required.