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Junos Os EvolvedOperating system · Juniper

CVE-2022-22227

MEDIUM · 5.3 CVSS v3.1 Published 2022-10-18
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
62/100
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 Improper Check for Unusual or Exceptional Conditions vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS Evolved on ACX7000 Series allows an unauthenticated network-based attacker to cause a partial Denial of Service (DoS). On receipt of specific IPv6 transit traffic, Junos OS Evolved on ACX7100-48L, ACX7100-32C and ACX7509 sends this traffic to the Routing Engine (RE) instead of forwarding it, leading to increased CPU utilization of the RE and a partial DoS. This issue only affects systems configured with IPv6. This issue does not affect ACX7024 which is supported from 22.3R1-EVO onwards where the fix has already been incorporated as indicated in the solution section. This issue affects Juniper Networks Junos OS Evolved on ACX7100-48L, ACX7100-32C, ACX7509: 21.1-EVO versions prior to 21.1R3-S2-EVO; 21.2-EVO versions prior to 21.2R3-S2-EVO; 21.3-EVO versions prior to 21.3R3-EVO; 21.4-EVO versions prior to 21.4R1-S1-EVO, 21.4R2-EVO. This issue does not affect Juniper Networks Junos OS Evolved versions prior to 21.1R1-EVO.

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 check for unusual conditions in the Packet Forwarding Engine (PFE) causes specific IPv6 transit traffic on ACX7100-48L, ACX7100-32C, and ACX7509 devices to be incorrectly sent to the Routing Engine instead of being forwarded, resulting in increased RE CPU utilization and partial DoS.

MitigationUpgrade Junos OS Evolved to the fixed versions (21.1R3-S2-EVO, 21.2R3-S2-EVO, 21.3R3-EVO, 21.4R1-S1-EVO, or 21.4R2-EVO). If immediate upgrade is not possible, consider IPv6 traffic filtering or rate limiting as a temporary workaround.

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
Junos Os EvolvedOperating system
Affected:= 21.1= 21.2= 21.3= 21.4

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
Unchanged
Confidentiality
None
Integrity
None
Availability
Low

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

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 'show system information' to confirm the device is an ACX7100-48L, ACX7100-32C, or ACX7509
    Affected if Device model matches one of the three affected models
  2. Verify Junos OS Evolved version
    Run 'show version' or 'show system information' to check the installed Junos OS Evolved version
    Affected if Version is 21.1, 21.2, 21.3, or 21.4
  3. Confirm IPv6 transit traffic is present
    Run 'show route table inet6' to verify active IPv6 routes, and monitor interface traffic with 'show interface statistics' for IPv6 packet flow
    Affected if Device is processing IPv6 transit traffic
  4. Check for elevated Routing Engine CPU
    Run 'show system processes summary' or 'show system cpu' to monitor RE CPU utilization
    Affected if RE CPU utilization is abnormally high while IPv6 traffic is flowing
  5. Inspect PFE forwarding statistics
    Run 'show pfe statistics traffic' or equivalent command to check if IPv6 packets are being forwarded to the RE instead of being switched
    Affected if IPv6 transit traffic is being sent to the Routing Engine instead of being forwarded by the PFE

Device is affected if it is an ACX7100-48L, ACX7100-32C, or ACX7509 running Junos OS Evolved version 21.1, 21.2, 21.3, or 21.4 and processing IPv6 transit traffic that is causing elevated RE CPU usage.

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 Evolved to the fixed versions (21.1R3-S2-EVO, 21.2R3-S2-EVO, 21.3R3-EVO, 21.4R1-S1-EVO, or 21.4R2-EVO). If immediate upgrade is not possible, consider IPv6 traffic filtering or rate limiting as a temporary workaround.

Recommended fix High confidence

Upgrade to 21.1R3-S2-EVO, 21.2R3-S2-EVO, 21.3R3-EVO, or 21.4R2-EVO (or later) depending on your current branch

  1. 1. Verify the current Junos OS Evolved version running on the ACX7100-48L, ACX7100-32C, or ACX7509 device using 'show version'
  2. 2. Confirm IPv6 is configured on the system using 'show configuration protocols ipv6'
  3. 3. Schedule a maintenance window for the upgrade (this will require a system reboot)
  4. 4. Download the appropriate fixed EVO version (21.1R3-S2-EVO, 21.2R3-S2-EVO, 21.3R3-EVO, or 21.4R2-EVO or later) from the Juniper Networks support portal
  5. 5. Upload the Junos OS Evolved software package to the device's /var/tmp directory
  6. 6. Initiate the software installation using 'request system software add /var/tmp/<package-name>'
  7. 7. Reboot the device using 'request system reboot' to complete the installation
  8. 8. After reboot, verify the new version is running with 'show version' and confirm IPv6 functionality is restored
Caveat Standard Junos OS Evolved upgrade precautions apply - verify compatibility with other network devices and ensure configuration backup before upgrade

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

Fix this in Junos Os Evolved Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
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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-2022-22227 in production — separate from our analysis above.

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What this is

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