Improper Check for Unusual or Exceptional Conditions in Junos OS - CVE-2026-57022

Detailed vulnerability description

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

The vulnerability exists due to improper check for unusual or exceptional conditions error in the Packet Forwarding Engine (PFE). A remote non-authenticated attacker can cause a Denial-of-Service (DoS).

When an affected device initiates a TCP connection to an attacker-controlled system that responds with a specific packet, this causes a PFE crash and restart, which affects all services until the system has automatically recovered.

This issue can happen among others in the following scenarios: ALG, SSL proxy, UTM, RTLOG, AppQoE probing, AAMW, ICAP, URL filtering.

How to mitigate CVE-2026-57022

Sources

• https://supportportal.juniper.net/s/article/2026-07-Security-Bulletin-Junos-OS-MX-Series-with-SPC3-SRX-Series-Specific-packet-in-response-to-a-TCP-connection-establishment-by-the-affected-device-can-crash-the-PFE-CVE-2026-57022