CVE-2026-57022

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Denial-of-Service in Juniper Junos OS on MX and SRX Series

Publication date: 2026-07-09

Last updated on: 2026-07-10

Assigner: Juniper Networks, Inc.

Description

An Improper Check for Unusual or Exceptional Conditions vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS on MX with SPC3 and SRX Series allows an unauthenticated, network-based attacker to 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. This issue affects Junos OS on MX Series with SPC3, SRX5k Series with SPC3, SRX1600 Series, SRX2300 Series, SRX4000 Series, and vSRX Series: * all versions before 23.2R2-S4, * 23.4 versions before 23.4R2-S5, * 24.2 versions before 24.2R2.

CVSS Scores

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Meta Information

Published

2026-07-09

Last Modified

2026-07-10

Generated

2026-07-11

AI Q&A

2026-07-10

EPSS Evaluated

N/A

NVD

CVE-2026-57022

EUVD

EUVD-2026-42709

Affected Vendors & Products

Vendor	Product	Version / Range
juniper_networks	junos_os	to 23.2R2-S4 (exc)
juniper_networks	junos_os	to 23.4R2-S5 (exc)
juniper_networks	junos_os	to 24.2R2 (exc)

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.

Attack-Flow Graph

Executive Summary

This vulnerability is an Improper Check for Unusual or Exceptional Conditions in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS on MX with SPC3 and SRX Series devices.

An unauthenticated, network-based attacker can exploit this by initiating a TCP connection to an affected device, which then connects to the attacker-controlled system. If the attacker responds with a specific packet, it causes the PFE to crash and restart.

This crash affects all services on the device until it automatically recovers. The issue can occur in various scenarios such as ALG, SSL proxy, UTM, RTLOG, AppQoE probing, AAMW, ICAP, and URL filtering.

Impact Analysis

The vulnerability can cause a Denial-of-Service (DoS) condition on affected Juniper devices.

When exploited, the Packet Forwarding Engine crashes and restarts, disrupting all services running on the device until recovery is complete.

This disruption can lead to network outages or degraded network performance, impacting availability and potentially causing operational interruptions.

Mitigation Strategies

To mitigate this vulnerability, you should upgrade affected Junos OS devices to a fixed version. The affected versions are all versions before 23.2R2-S4, 23.4 versions before 23.4R2-S5, and 24.2 versions before 24.2R2.

Until you can upgrade, consider limiting or blocking TCP connections to attacker-controlled systems that could send the specific packets causing the Packet Forwarding Engine (PFE) crash.

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