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JunosOperating system · Juniper

CVE-2023-22391

HIGH · 7.5 CVSS v3.1 Published 2023-01-13
Fix available
A fix is available. Upgrade to 19.4 or later.
See remediation →
84/100
Remediation priority · High
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
A vulnerability in class-of-service (CoS) queue management in Juniper Networks Junos OS on the ACX2K Series devices allows an unauthenticated network-based attacker to cause a Denial of Service (DoS). Specific packets are being incorrectly routed to a queue used for other high-priority traffic such as BGP, PIM, ICMP, ICMPV6 ND and ISAKMP. Due to this misclassification of traffic, receipt of a high rate of these specific packets will cause delays in the processing of other traffic, leading to a Denial of Service (DoS). Continued receipt of this amount of traffic will create a sustained Denial of Service (DoS) condition. This issue affects Juniper Networks Junos OS on ACX2K Series: All versions prior to 19.4R3-S9; All 20.2 versions; 20.3 versions prior to 20.3R3-S6 on ACX2K Series; 20.4 versions prior to 20.4R3-S4 on ACX2K Series; All 21.1 versions; 21.2 versions prior to 21.2R3-S3 on ACX2K Series. Note: This issues affects legacy ACX2K Series PPC-based devices. This platform reached Last Supported Version (LSV) as of the Junos OS 21.2 Release.

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

A class-of-service (CoS) queue misclassification vulnerability in Juniper Junos OS on ACX2K Series devices causes specific network packets to be incorrectly routed to high-priority queues used for BGP, PIM, ICMP, ICMPV6 ND, and ISAKMP traffic. An unauthenticated attacker sending these specific packets at high volume can overwhelm the system and cause sustained DoS.

MitigationApply vendor-supplied patches (19.4R3-S9, 20.3R3-S6, 20.4R3-S4, 21.2R3-S3 or later) or upgrade to a currently supported platform, as ACX2K Series reached End of Life with LSV at 21.2.

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:< 19.4= 19.4= 20.2= 20.3= 20.4= 21.1= 21.2

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
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/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 physical device labeling to confirm it is an ACX2K Series device (ACX2000, ACX2200, ACX4000, etc.)
    Affected if Device is NOT an ACX2K Series device - the vulnerability only affects ACX2K Series platforms
  2. Check Junos OS version
    Run 'show version' or 'show version detail' to display the installed Junos OS version
    Affected if Version matches any of: < 19.4, 19.4R1 through 19.4R3, 20.2Rx, 20.3Rx, 20.4Rx, 21.1Rx, 21.2Rx (specifically 19.4, 20.2, 20.3, 20.4, 21.1, 21.2 as listed in affected versions)
  3. Verify CoS configuration exists
    Run 'show configuration class-of-service' to display the CoS configuration
    Affected if No CoS configuration exists - the vulnerability requires CoS queue classification to be configured
  4. Check queue mapping for affected protocols
    Run 'show configuration class-of-service classifiers' and 'show configuration class-of-service rewrite-rules' to inspect how BGP, PIM, ICMP, ICMPV6 ND, and ISAKMP traffic is classified to queues
    Affected if Any of these protocols (BGP, PIM, ICMP, ICMPV6 ND, ISAKMP) are mapped to high-priority queues (typically queue 0 or expedited-forwarding queues) in the CoS configuration
  5. Inspect forwarding class configuration
    Run 'show configuration class-of-service forwarding-classes' to view forwarding class assignments and their queue mappings
    Affected if Forwarding classes for the affected protocols are mapped to queues designated for high-priority traffic (BGP/PIM/ICMP priority queues)

A user is affected if they are running any vulnerable Junos version (19.4, 20.2, 20.3, 20.4, 21.1, 21.2) on ACX2K Series hardware with CoS queue classification configured that maps BGP, PIM, ICMP, ICMPV6 ND, or ISAKMP traffic to high-priority queues.

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
Upgrade available Upgrade to 19.4 or later
Fixed in 19.4
Interim mitigation

Apply vendor-supplied patches (19.4R3-S9, 20.3R3-S6, 20.4R3-S4, 21.2R3-S3 or later) or upgrade to a currently supported platform, as ACX2K Series reached End of Life with LSV at 21.2.

Recommended fix High confidence

19.4R3-S9, 20.3R3-S6, 20.4R3-S4, or 21.2R3-S3 (depending on which branch you are on)

  1. 1. Identify the current Junos OS version on the ACX2K Series device using 'show version'
  2. 2. Determine the appropriate fixed release based on your current version branch: For 19.x branches, upgrade to 19.4R3-S9 or later; For 20.2, upgrade to a later branch like 20.3R3-S6+ or 20.4R3-S4+; For 20.3, upgrade to 20.3R3-S6 or later; For 20.4, upgrade to 20.4R3-S4 or later; For 21.1, upgrade to 21.2R3-S3 or later; For 21.2, upgrade to 21.2R3-S3 or later
  3. 3. Download the appropriate Junos OS upgrade image from the Juniper Networks website
  4. 4. Back up the current configuration using 'request system configuration rescue save'
  5. 5. Upgrade the device using 'request system software add <package-name>' with the appropriate reboot options
  6. 6. After upgrade, verify the CoS queue configuration is functioning correctly using 'show class-of-service queue'
Caveat ACX2K Series is a legacy PPC-based platform that reached Last Supported Version (LSV) as of Junos OS 21.2 Release - no further updates beyond 21.2 branch; ensure compatibility with existing network design before upgrading

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

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-2023-22391 in production — separate from our analysis above.

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