SB2025050107 - Improper check for unusual or exceptional conditions in Juniper Junos OS

Security Bulletin ID SB2025050107

Severity

Medium

Patch available

YES

Number of vulnerabilities 1

Exploitation vector Remote access

Highest impact Denial of service

Breakdown by Severity

Low
Medium
High
Critical

Description

This security bulletin contains information about 1 security vulnerability.

1) Improper check for unusual or exceptional conditions (CVE-ID: CVE-2025-21594)

The vulnerability allows a remote non-authenticated attacker to cause perform a denial of service (DoS) attack.

An Improper Check for Unusual or Exceptional Conditions vulnerability in the pfe (packet forwarding engine) of Juniper Networks Junos OS on MX Series causes a port within a pool to be blocked leading to Denial of Service (DoS).

In a DS-Lite (Dual-Stack Lite) and NAT (Network Address Translation) scenario, when crafted IPv6 traffic is received and prefix-length is set to 56, the ports assigned to the user will not be freed.

Remediation

Install update from vendor's website.

References

https://supportportal.juniper.net/s/article/2025-04-Security-Bulletin-Junos-OS-MX-Series-In-DS-lite-and-NAT-senario-receipt-of-crafted-IPv4-traffic-causes-port-block-CVE-2025-21594