CVE-2026-33773Network attack vector

Filter bypass via omitted duplicate egress rule

Published Apr 9, 2026 · Updated Apr 9, 2026

Incorrect resource initialization in Juniper Networks Junos OS 23.4R2-S6 and 24.2R2-S3 allows remote attackers to bypass egress filters. The packet forwarding engine applies only one filter when the same family inet or inet6 filter is configured for output on both an IRB and a physical interface. The issue is limited to EX4100, EX4400, EX4650, and QFX5120 devices with that dual-interface configuration, allowing traffic blocked by the omitted filter to reach downstream networks.

CVSS severity6.9
Medium
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect resource initialization in Juniper Networks Junos OS 23.4R2-S6 and 24.2R2-S3 allows remote attackers to bypass egress filters. The packet forwarding engine applies only one filter when the same family inet or inet6 filter is configured for output on both an IRB and a physical interface. The issue is limited to EX4100, EX4400, EX4650, and QFX5120 devices with that dual-interface configuration, allowing traffic blocked by the omitted filter to reach downstream networks.

The record

CVE
CVE-2026-33773
Published
Apr 9, 2026
Updated
Apr 9, 2026
Vendor
Juniper Networks
Product
Junos OS
Classifications
CWE-1419, T1562.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=23.4R2-S6 <23.4R2-S7
  2. Affected versionversion=24.2R2-S3 <24.2R2-S4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Juniper Networks · Junos OSversion=23.4R2-S6 <23.4R2-S7; version=24.2R2-S3 <24.2R2-S4

Published CVSS scores

6.9Juniper NetworksCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N
5.8Juniper NetworksCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1419Incorrect Initialization of Resource
T1562.004Impair Defenses: Disable or Modify System Firewall

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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