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JunosOperating system · Juniper

CVE-2026-33773

MEDIUM · 5.8 CVSS v3.1 Published 2026-04-09
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
67/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

This is an incorrect initialization vulnerability in the packet forwarding engine where applying the same family inet or inet6 filter on both an IRB interface and a physical interface as egress filter causes only one filter to be applied, allowing traffic that should be blocked to pass through to downstream networks.

MitigationAvoid applying the same filter family to both IRB and physical interfaces as egress filters on affected EX and QFX devices; redesign filter configurations to use unique filter terms or apply filters differently to achieve intended policy.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
JunosOperating system
Affected:= 23.4= 24.2

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify IRB interfaces with egress filters
    Run 'show interfaces irb' or review configuration for any IRB (Integrated Routing and Bridging) interfaces that have egress filter configurations applied.
    Affected if IRB interfaces exist with family inet or inet6 egress filters configured
  2. Identify physical interfaces with egress filters
    Run 'show configuration | match egress' or review firewall filter configurations applied to physical interfaces in the egress direction.
    Affected if Physical interfaces have family inet or inet6 egress filters applied
  3. Check for filter family overlap
    Compare the filter families (inet vs inet6) applied to IRB interfaces versus physical interfaces. Look for configurations where both interface types use the same address family.
    Affected if Both IRB and physical interfaces have egress filters using the same family (both inet or both inet6)
  4. Verify filter is applied to both interface types
    Use 'show configuration' or 'show firewall' commands to confirm identical or similar filters are applied to both an IRB interface and a physical interface as egress filters.
    Affected if The same filter or filters of the same family are applied to both an IRB interface and a physical interface in the egress direction

Your environment is affected if you have IRB interfaces and physical interfaces both configured with egress filters using the same address family (inet or inet6), as only one filter will be applied due to the initialization flaw.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Avoid applying the same filter family to both IRB and physical interfaces as egress filters on affected EX and QFX devices; redesign filter configurations to use unique filter terms or apply filters differently to achieve intended policy.

Fix this in Junos Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-33773 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
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  • Version or environment caveats, and links to real fixes
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