High [CVE-2026-21914] Improper Locking vulnerability in the GTP plugin of Juniper Networks Junos OS on SRX Series
This high-severity Juniper Networks advisory covers CVE-2026-21914 affecting Junos, Junos OS, SRX.
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Summary
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,
- all versions
Official advisory · high-confidence parse· fetched 2 months ago·verify at source
- 22.4R3-S8
- 23.2R2-S5
- 23.4R2-S6
- 24.2R2-S3
- 24.4R2-S2
- 25.2R1-S1
Official advisory · high-confidence parse· fetched 2 months ago·verify at source
Mitigation
Upgrade to a fixed release: 22.4R3-S8, 23.2R2-S5, 23.4R2-S6, 24.2R2-S3, 24.4R2-S2, 25.2R1-S1. That is the remediation for this advisory.
The vendor advisory may list additional interim mitigations or workarounds not captured here — review it before change work.
Official advisory · high-confidence parse· fetched 2 months ago·verify at source
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