An Improper Check for Unusual or Exceptional Conditions vulnerability in the packet forwarding engine (PFE) of Juniper Networks Junos OS on EX4k Series and QFX5k Series platforms allows an unauthenticated network-adjacent attacker flapping an interface to cause traffic between VXLAN Network Identifiers (VNIs) to drop, leading to a Denial of Service (DoS). On all EX4k and QFX5k platforms, a link flap in an EVPN-VXLAN configuration Link Aggregation Group (LAG) results in Inter-VNI traffic dropping when there are multiple load-balanced next-hop routes for the same destination. This issue is only applicable to systems that support EVPN-VXLAN Virtual Port-Link Aggregation Groups (VPLAG), such as the QFX5110, QFX5120, QFX5200, EX4100, EX4300, EX4400, and EX4650. Service can only be restored by restarting the affected FPC via the 'request chassis fpc restart slot <slot-number>' command. This issue affects Junos OS on EX4k and QFX5k Series: * all versions before 21.4R3-S12, * all versions of 22.2 * from 22.4 before 22.4R3-S8, * from 23.2 before 23.2R2-S5, * from 23.4 before 23.4R2-S5, * from 24.2 before 24.2R2-S3, * from 24.4 before 24.4R2.
This vulnerability carries a MEDIUM severity rating with a CVSS v3.1 score of 6.5, indicating it requires adjacent network access with relatively low complexity without requiring user interaction and does not require pre-existing privileges . The vulnerability impacts and availability (service disruption) for affected systems. Impacting 19 products from juniper, from juniper, from juniper and 16 others, organizations running these solutions should prioritize assessment and patching.
Reported in 2026, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.
2026-01-15T21:16:06.920
2026-06-17T10:19:08.410
Analyzed
CVSSv3.1: 6.5 (MEDIUM)
| Type | Vendor | Product | Version/Range | Vulnerable? |
|---|---|---|---|---|
| Operating System | juniper | junos | < 21.4 | Yes |
| Operating System | juniper | junos | 21.4 | Yes |
| Operating System | juniper | junos | 21.4 | Yes |
| Operating System | juniper | junos | 21.4 | Yes |
| Operating System | juniper | junos | 21.4 | Yes |
| Operating System | juniper | junos | 21.4 | Yes |
| Operating System | juniper | junos | 21.4 | Yes |
| Operating System | juniper | junos | 21.4 | Yes |
| Operating System | juniper | junos | 21.4 | Yes |
| Operating System | juniper | junos | 21.4 | Yes |
| Operating System | juniper | junos | 21.4 | Yes |
| Operating System | juniper | junos | 21.4 | Yes |
| Operating System | juniper | junos | 21.4 | Yes |
| Operating System | juniper | junos | 21.4 | Yes |
| Operating System | juniper | junos | 21.4 | Yes |
| Operating System | juniper | junos | 21.4 | Yes |
| Operating System | juniper | junos | 21.4 | Yes |
| Operating System | juniper | junos | 21.4 | Yes |
| Operating System | juniper | junos | 21.4 | Yes |
| Operating System | juniper | junos | 21.4 | Yes |
| Operating System | juniper | junos | 22.2 | Yes |
| Operating System | juniper | junos | 22.4 | Yes |
| Operating System | juniper | junos | 22.4 | Yes |
| Operating System | juniper | junos | 22.4 | Yes |
| Operating System | juniper | junos | 22.4 | Yes |
| Operating System | juniper | junos | 22.4 | Yes |
| Operating System | juniper | junos | 22.4 | Yes |
| Operating System | juniper | junos | 22.4 | Yes |
| Operating System | juniper | junos | 22.4 | Yes |
| Operating System | juniper | junos | 22.4 | Yes |
| Operating System | juniper | junos | 22.4 | Yes |
| Operating System | juniper | junos | 22.4 | Yes |
| Operating System | juniper | junos | 22.4 | Yes |
| Operating System | juniper | junos | 22.4 | Yes |
| Operating System | juniper | junos | 22.4 | Yes |
| Operating System | juniper | junos | 22.4 | Yes |
| Operating System | juniper | junos | 23.2 | Yes |
| Operating System | juniper | junos | 23.2 | Yes |
| Operating System | juniper | junos | 23.2 | Yes |
| Operating System | juniper | junos | 23.2 | Yes |
| Operating System | juniper | junos | 23.2 | Yes |
| Operating System | juniper | junos | 23.2 | Yes |
| Operating System | juniper | junos | 23.2 | Yes |
| Operating System | juniper | junos | 23.2 | Yes |
| Operating System | juniper | junos | 23.2 | Yes |
| Operating System | juniper | junos | 23.4 | Yes |
| Operating System | juniper | junos | 23.4 | Yes |
| Operating System | juniper | junos | 23.4 | Yes |
| Operating System | juniper | junos | 23.4 | Yes |
| Operating System | juniper | junos | 23.4 | Yes |
| Operating System | juniper | junos | 23.4 | Yes |
| Operating System | juniper | junos | 23.4 | Yes |
| Operating System | juniper | junos | 23.4 | Yes |
| Operating System | juniper | junos | 23.4 | Yes |
| Operating System | juniper | junos | 24.2 | Yes |
| Operating System | juniper | junos | 24.2 | Yes |
| Operating System | juniper | junos | 24.2 | Yes |
| Operating System | juniper | junos | 24.2 | Yes |
| Operating System | juniper | junos | 24.2 | Yes |
| Operating System | juniper | junos | 24.2 | Yes |
| Operating System | juniper | junos | 24.2 | Yes |
| Operating System | juniper | junos | 24.4 | Yes |
| Operating System | juniper | junos | 24.4 | Yes |
| Operating System | juniper | junos | 24.4 | Yes |
| Operating System | juniper | junos | 24.4 | Yes |
| Hardware | juniper | ex4000 | - | No |
| Hardware | juniper | ex4100 | - | No |
| Hardware | juniper | ex4100-f | - | No |
| Hardware | juniper | ex4100-h | - | No |
| Hardware | juniper | ex4300 | - | No |
| Hardware | juniper | ex4400 | - | No |
| Hardware | juniper | ex4600 | - | No |
| Hardware | juniper | ex4650 | - | No |
| Hardware | juniper | qfx5110 | - | No |
| Hardware | juniper | qfx5120 | - | No |
| Hardware | juniper | qfx5130 | - | No |
| Hardware | juniper | qfx5200 | - | No |
| Hardware | juniper | qfx5210 | - | No |
| Hardware | juniper | qfx5220 | - | No |
| Hardware | juniper | qfx5230-64cd | - | No |
| Hardware | juniper | qfx5240 | - | No |
| Hardware | juniper | qfx5241 | - | No |
| Hardware | juniper | qfx5700 | - | No |
SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For juniper's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.