CVE-2026-33773

Summary

An Incorrect Initialization of Resource vulnerability in the packet forwarding engine (pfe) of Juniper Networks Junos OS on specific EX Series and QFX Series device allows an unauthenticated, network-based attacker to cause an integrity impact to downstream networks.

When the same family inet or inet6 filter is applied on an IRB interface and on a physical interface as egress filter on EX4100, EX4400, EX4650 and QFX5120 devices, only one of the two filters will be applied, which can lead to traffic being sent out one of these interfaces which should have been blocked.

This issue affects Junos OS on EX Series and QFX Series:

• 23.4 version 23.4R2-S6,
• 24.2 version 24.2R2-S3.

No other Junos OS versions are affected.

Affected Software

Weaknesses

• CWE-1419: CWE-1419 Incorrect Initialization of Resource

Workarounds

Two different workarounds are available:

1. create the same filter but under a different name and apply that to one of the interfaces, so that each interface has a unique copy of the filter in question as shown in the following example:

user@host# copy … <filter> to … <filter2> user@host# set interfaces irb unit <unit2> family inet/inet6 filter output <filter2>

2. configure the filter as "interface specific" by adding the keyword to the filter definition:

[ firewall family inet/inet6 filter <filter> interface-specific ]

which implicitly creates a copy of the original filter per applied interface.

ADP Enrichment

CISA ADP Vulnrichment

• SSVC:
• Exploitation: none
  • Automatable: yes
  • Technical Impact: partial

References

• https://kb.juniper.net/JSA107815

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