Executive brief
A vulnerability in Juniper Networks Junos OS can allow a remote attacker to crash the networking hardware, leading to a total loss of service. This occurs when the device attempts to connect to a malicious system that sends a specifically crafted response. The crash affects critical security and traffic management services until the system automatically restarts and recovers.
Technical details
An Improper Check for Unusual or Exceptional Conditions (CWE-754) exists in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS. The vulnerability is triggered when an affected device (MX with SPC3 or SRX Series) initiates a TCP connection to an attacker-controlled system that responds with a specific, malformed packet. This causes the PFE to crash and restart, impacting services such as SSL proxy, UTM, and ALG. The attack requires the device to initiate the connection, making the attack vector network-based but requiring specific conditions to trigger. Patches are available in versions 23.2R2-S4, 23.4R2-S5, 24.2R2, and subsequent releases.
Affected products
- Juniper Networks Junos OS All versions before 23.2R2-S4; 23.4 versions before 23.4R2-S5; 24.2 versions before 24.2R2
Timeline
- 2026-07-09: advisory: Initial advisory published by Juniper Networks