CVE-2026-57031

Summary

An Improper Check for Unusual or Exceptional Conditions vulnerability in the packet forwarding engine (PFE) of Juniper Networks Junos OS on MX Series allows adjacent subscribers to bypass configured firewall filters.

On MX Series devices with MPC10/11, LC4800/9600, and MX304 with subscribers configured on static interfaces, ingress firewall filters are not enforced, so that neither protocol level nor upstream bandwidth limitation are in effect. 

This issue affects Junos OS on MX with MPC10/11, LC4800/9600/4802, and MX304:

  • 23.2 versions from 23.2R2-S1 before 23.2R2-S7,
  • 23.4 versions from 23.4R2 before 23.4R2-S7,
  • 24.2 versions before 24.2R2-S3,
  • 24.4 versions before 24.4R2-S2,
  • 25.2 versions before 25.2R2.

Affected Software

VendorProductVersion RangeStatus
Juniper NetworksJunos OS23.2R2-S1 < 23.2R2-S7affected
Juniper NetworksJunos OS23.4R2 < 23.4R2-S7affected
Juniper NetworksJunos OS24.2 < 24.2R2-S3affected
Juniper NetworksJunos OS24.4 < 24.4R2-S2affected
Juniper NetworksJunos OS25.2 < 25.2R2affected

Weaknesses

  • CWE-754: CWE-754 Improper Check for Unusual or Exceptional Conditions

Workarounds

There are no known workarounds for this issue.

References