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JunosOperating system · Juniper

CVE-2023-44183

MEDIUM · 5.3 CVSS v3.1 Published 2023-10-13
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
58/100
Remediation priority · Elevated
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 Improper Input Validation vulnerability in the VxLAN packet forwarding engine (PFE) of Juniper Networks Junos OS on QFX5000 Series, EX4600 Series devices allows an unauthenticated, adjacent attacker, sending two or more genuine packets in the same VxLAN topology to possibly cause a DMA memory leak to occur under various specific operational conditions. The scenario described here is the worst-case scenario. There are other scenarios that require operator action to occur. An indicator of compromise may be seen when multiple devices indicate that FPC0 has gone missing when issuing a show chassis fpc command for about 10 to 20 minutes, and a number of interfaces have also gone missing. Use the following command to determine if FPC0 has gone missing from the device. show chassis fpc detail This issue affects: Juniper Networks Junos OS on QFX5000 Series, EX4600 Series: * 18.4 version 18.4R2 and later versions prior to 20.4R3-S8; * 21.1 version 21.1R1 and later versions prior to 21.2R3-S6; * 21.3 versions prior to 21.3R3-S5; * 21.4 versions prior to 21.4R3-S4; * 22.1 versions prior to 22.1R3-S3; * 22.2 versions prior to 22.2R3-S1; * 22.3 versions prior to 22.3R2-S2, 22.3R3; * 22.4 versions prior to 22.4R2.

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

Improper input validation in the VxLAN packet forwarding engine (PFE) of Juniper Junos OS on QFX5000 and EX4600 Series allows an adjacent attacker sending specific VxLAN packets to trigger a DMA memory leak. This memory leak eventually causes FPC0 and multiple interfaces to go missing from the device, observed via 'show chassis fpc detail' after 10-20 minutes of exploitation.

MitigationUpgrade Junos OS to the fixed versions specified (20.4R3-S8, 21.2R3-S6, 21.3R3-S5, 21.4R3-S4, 22.1R3-S3, 22.2R3-S1, 22.3R2-S2/22.3R3, or 22.4R2 or later). Monitor FPC status using 'show chassis fpc detail' to detect early signs of the memory leak.

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:= 18.4= 19.1= 19.2= 19.3= 19.4= 20.1= 20.2= 20.3= 20.4= 21.1= 21.2= 21.3

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
Adjacent
Complexity
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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

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 device model
    Run 'show chassis hardware' or check the device model to confirm it is a QFX5000 or EX4600 series switch
    Affected if Device is not a QFX5000 or EX4600 series model
  2. Check Junos OS version
    Run 'show version' to obtain the installed Junos OS version
    Affected if Version matches any of the affected releases: 18.4, 19.1, 19.2, 19.3, 19.4, 20.1, 20.2, 20.3, 20.4, 21.1, 21.2, or 21.3
  3. Verify VxLAN configuration
    Run 'show configuration protocols vxlan' to check if VxLAN is configured on the device
    Affected if VxLAN feature is enabled and configured
  4. Monitor FPC status for missing instances
    Run 'show chassis fpc detail' and observe if FPC0 or multiple interfaces are missing or offline
    Affected if FPC0 shows as missing, offline, or not present in the output after sustained traffic
  5. Check for DMA memory exhaustion
    Run 'show chassis fpc detail' repeatedly over 10-20 minutes and compare memory utilization trends
    Affected if FPC memory usage steadily increases with no decrease, leading to FPC disappearance

Device is affected if it is a QFX5000 or EX4600 series switch running a vulnerable Junos version (18.4-21.3) with VxLAN enabled, and FPC0 or interfaces become missing during normal operation.

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.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade Junos OS to the fixed versions specified (20.4R3-S8, 21.2R3-S6, 21.3R3-S5, 21.4R3-S4, 22.1R3-S3, 22.2R3-S1, 22.3R2-S2/22.3R3, or 22.4R2 or later). Monitor FPC status using 'show chassis fpc detail' to detect early signs of the memory leak.

Recommended fix High confidence

Junos OS 20.4R3-S8 or later (for 18.4/19.x trains); 21.2R3-S6 or later (for 21.1); 21.3R3-S5 or later (for 21.3); 21.4R3-S4 or later (for 21.4); 22.1R3-S3 or later (for 22.1); 22.2R3-S1 or later (for 22.2); 22.3R3 or 22.3R2-S2 or later (for 22.3); 22.4R2 or later (for 22.4)

  1. 1. Identify the current Junos OS version on the affected QFX5000 Series or EX4600 Series device using `show version`
  2. 2. Identify the specific release train (18.4, 19.x, 21.1, 21.2, 21.3, 21.4, 22.1, 22.2, 22.3, or 22.4) currently running
  3. 3. Plan the upgrade to the appropriate fixed version for your release train: For 18.4/19.x train, upgrade to 20.4R3-S8 or later; For 21.1 train, upgrade to 21.2R3-S6 or later; For 21.3 train, upgrade to 21.3R3-S5 or later; For 21.4 train, upgrade to 21.4R3-S4 or later; For 22.1 train, upgrade to 22.1R3-S3 or later; For 22.2 train, upgrade to 22.2R3-S1 or later; For 22.3 train, upgrade to 22.3R2-S2
  4. 4. Download the appropriate Junos OS upgrade image from the Juniper Networks support portal
  5. 5. Back up the current configuration using `request system configuration save` or `file copy`
  6. 6. Upload the upgrade image to the device and initiate the upgrade with `request system software add <package-name>`
  7. 7. Reboot the device after upgrade completes using `request system reboot`
  8. 8. After reboot, verify the new version with `show version`
Caveat Standard Junos OS upgrade considerations apply - review release notes for compatibility, ensure configuration compatibility, and plan for appropriate maintenance window as upgrades require reboot

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Junos Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
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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

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Peer-ranked notes from engineers who’ve handled CVE-2023-44183 in production — separate from our analysis above.

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