An Improper Locking vulnerability in the GTP plugin of Juniper Networks Junos OS on SRX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (Dos).

If an SRX Series device receives a specifically malformed GPRS Tunnelling Protocol (GTP) Modify Bearer Request message, a lock is acquired and never released. This results in other threads not being able to acquire a lock themselves, causing a watchdog timeout leading to FPC crash and restart. This issue leads to a complete traffic outage until the device has automatically recovered.

This issue affects Junos OS on SRX Series:

• all versions before 22.4R3-S8,
• 23.2 versions before 23.2R2-S5,
• 23.4 versions before 23.4R2-S6,
• 24.2 versions before 24.2R2-S3,
• 24.4 versions before 24.4R2-S2,
• 25.2 versions before 25.2R1-S1, 25.2R2.

To be exposed to this issue the device needs to be configured with a GTP profile as follows:

[ security policies ... policy <policy-name> then permit application-services gtp-profile <profile-name> ]

Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

This issue was seen during production usage.

The following software releases have been updated to resolve this specific issue: 22.4R3-S8, 23.2R2-S5, 23.4R2-S6, 24.2R2-S3, 24.4R2-S2, 25.2R1-S1, 25.2R2, 25.4R1, and all subsequent releases.

This issue is being tracked as 1882028 which is visible on the Customer Support website.

Note: Juniper SIRT's policy is not to evaluate releases which are beyond End of Engineering (EOE) or End of Life (EOL).

There are no known workarounds for this issue.

2026-01-14: Initial Publication

• KB16613: Overview of the Juniper Networks SIRT Quarterly Security Bulletin Publication Process [juniper.net]
• KB16765: In which releases are vulnerabilities fixed? [juniper.net]
• KB16446: Common Vulnerability Scoring System (CVSS) and Juniper's Security Advisories [juniper.net]
• Report a Security Vulnerability - How to Contact the Juniper Networks Security Incident Response Team