CVE-2026-102083: SRX Series: With WebFiltering enabled prolonged HTTP session load can cause a crash

In short

An improper resource locking flaw in the UTM processing of Junos OS on SRX Series firewalls allows an unauthenticated, network-based attacker to cause a Denial-of- Service. When UTM WebFiltering is configured and the cloud server is unreachable, sustained HTTP traffic causes pending lookup requests to accumulate. Under high load, this accumulation leads to an invalid internal state during cleanup, crashing the UTM process and resulting in a complete service outage until the system recovers.

Written by a language model from the vendor's description. Versions, fixes and exploitation status on this page come straight from the vendor and CISA.

The vendor's description

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

When UTM WebFiltering is configured and the WebFiltering cloud server is unreachable, sustained HTTP traffic load may cause the UTM subsystem to crash and restart, which will lead to a complete service outage until the system has recovered. When category lookup requests cannot be completed, they accumulate internally. Under high load and specific timing conditions, an invalid internal state can occur during cleanup of pending WebFiltering lookups, resulting in a crash of the UTM process. This issue applies to both NextGeneration WebFiltering (NGWF) and Enhanced WebFiltering (EWF).

This issue affects Junos OS on SRX Series:

• 23.2 versions from 23.2R2 before 23.2R2-S7.7;
• 23.4 versions from 23.4R2 before 23.4R2-S8.13;
• 24.2 versions before 24.2R2-S5.5;
• 24.4 versions before 24.4R2-S4;
• 25.2 versions before 25.2R2-S1;
• 25.4 versions before 25.4R1-S3, 25.4R2.

Workarounds

There are no known workarounds for this issue.

Exploitation

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