dbcve.org
JunosOperating system · Juniper

CVE-2024-21593

MEDIUM · 6.5 CVSS v3.1 Published 2024-04-12
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
70/100
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 Check or Handling of Exceptional Conditions vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, adjacent attacker to cause a Denial of Service (DoS). If an attacker sends a specific MPLS packet, which upon processing, causes an internal loop, that leads to a PFE crash and restart. Continued receipt of these packets leads to a sustained Denial of Service (DoS) condition. Circuit cross-connect (CCC) needs to be configured on the device for it to be affected by this issue. This issue only affects MX Series with MPC10, MPC11, LC9600, and MX304. This issue affects: Juniper Networks Junos OS 21.4 versions from 21.4R3 earlier than 21.4R3-S5; 22.2 versions from 22.2R2 earlier than 22.2R3-S2; 22.3 versions from 22.3R1 earlier than 22.3R2-S2; 22.3 versions from 22.3R3 earlier than 22.3R3-S1 22.4 versions from 22.4R1 earlier than 22.4R2-S2, 22.4R3; 23.2 versions earlier than 23.2R1-S1, 23.2R2.

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 vulnerability in Juniper MX Series routers allows an adjacent, unauthenticated attacker to cause PFE crashes by sending specially crafted MPLS packets that trigger an internal processing loop. The issue only affects devices with Circuit Cross-Connect (CCC) configured on specific MPC line cards (MPC10, MPC11, LC9600, MX304).

MitigationUpgrade Junos OS to the specified fixed versions (21.4R3-S5, 22.2R3-S2, 22.3R2-S2/22.3R3-S1, 22.4R2-S2/22.4R3, 23.2R1-S1/23.2R2) and review CCC configurations to determine exposure scope.

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:= 21.4= 22.2= 22.3= 22.4= 23.2

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

CVSS:3.1/AV:A/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 the device model
    Run 'show chassis hardware' or 'show version' to confirm the device is a Juniper MX Series router
    Affected if The device is not an MX Series router (the vulnerability only affects MX Series)
  2. Check the Junos OS version
    Run 'show version' and compare the installed Junos version against the affected list: 21.4, 22.2, 22.3, 22.4, 23.2
    Affected if The installed version exactly matches one of the affected versions listed in the CVE (exact version match required)
  3. Verify presence of affected MPC line cards
    Run 'show chassis hardware' or 'show chassis fpc' and look for MPC10, MPC11, LC9600, or MX304 line cards
    Affected if One or more of these specific MPC line cards are present in the device
  4. Check for Circuit Cross-Connect (CCC) configuration
    Run 'show configuration protocols ccc' or 'show configuration | display set | match ccc' to determine if CCC is configured
    Affected if CCC (Circuit Cross-Connect) is actively configured on the device

The device is affected only if it is an MX Series router running exactly one of the affected Junos versions, has one of the specific MPC line cards (MPC10, MPC11, LC9600, MX304), AND has CCC configured - all three conditions must be true.

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 specified fixed versions (21.4R3-S5, 22.2R3-S2, 22.3R2-S2/22.3R3-S1, 22.4R2-S2/22.4R3, 23.2R1-S1/23.2R2) and review CCC configurations to determine exposure scope.

Recommended fix High confidence

Upgrade to 21.4R3-S5, 22.2R3-S2, 22.3R2-S2/22.3R3-S1, 22.4R2-S2/22.4R3, or 23.2R1-S1/23.2R2 depending on current branch

  1. 1. Identify the current Junos OS version running on the MX Series device using 'show version'
  2. 2. Verify the device has CCC (Circuit Cross-Connect) configured using 'show configuration protocols'
  3. 3. Confirm the device model is MX Series with MPC10, MPC11, LC9600, or MX304
  4. 4. Plan maintenance window as upgrade will require system reboot
  5. 5. Download the appropriate fixed version based on current branch: For 21.4 branch upgrade to 21.4R3-S5 or later; For 22.2 branch upgrade to 22.2R3-S2 or later; For 22.3 branch upgrade to 22.3R2-S2 or later (or 22.3R3-S1 if on 22.3R3); For 22.4 branch upgrade to 22.4R2-S2 or 22.4R3 or later; For 23.2 branch upgrade to 23.2R1-S1 or 23.2R2 or later
  6. 6. Upload the Junos OS upgrade package to the device
  7. 7. Initiate upgrade using 'request system software add <package>' command
  8. 8. After upgrade completes, reboot the device using 'request system reboot'
Caveat Standard Junos OS upgrade considerations apply - review release notes for any configuration changes, and ensure backup of configuration exists before upgrade

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 / QA4.0 h
22.0 hours of engineering $3,860
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2024-21593 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2024-21593 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data