CVE-2026-102077
Received
Received - Intake
Denial-of-Service in Juniper Junos OS on MX Series with SPC3
Vulnerability report for CVE-2026-102077, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-10-14
Last updated on: 2026-10-14
Assigner: Juniper Networks, Inc.
Description
Description
An Improper Check for Unusual or Exceptional Conditions vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS on MX Series with SPC3 allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS).
On MX Series with SPC3 line-card and source NAT configuration, when a specific malformed IPv6 packet is received, it is not dropped but instead a session is created and NAT resources are allocated. Continued receipt of such packets will eventually lead to session or resource exhaustion, which will impact all traffic through the device. To recover the device needs to be rebooted.
To monitor session usage, use the following:
show services sessions summary
To monitor source NAT resource usage, use the following:
show services nat pool
This issue affects Junos OS on MX Series with SPC3:
* All versions before 23.2R2-S4;
* 23.4 versions before 23.4R2-S5;
* 24.2 versions before 24.2R2.
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| Juniper | Networks | Junos OS 0 |
| Juniper | Networks | Junos OS 23.4 |
| Juniper | Networks | Junos OS 24.2 |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-754 | The product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product. |
