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Junos Os EvolvedOperating system · Juniper

CVE-2024-30403

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
A NULL Pointer Dereference vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS Evolved allows an unauthenticated, adjacent attacker to cause a Denial of Service (DoS). When Layer 2 traffic is sent through a logical interface, MAC learning happens. If during this process, the interface flaps, an Advanced Forwarding Toolkit manager (evo-aftmand-bt) core is observed. This leads to a PFE restart. The crash reoccurs if the same sequence of events happens, which will lead to a sustained DoS condition. This issue affects Juniper Networks Junos OS Evolved 23.2-EVO versions earlier than 23.2R1-S1-EVO, 23.2R2-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

A NULL pointer dereference in the Advanced Forwarding Toolkit manager (evo-aftmand-bt) occurs when Layer 2 traffic flows through a logical interface that flaps during the MAC learning process, causing the PFE to restart and creating a reproducible DoS condition.

MitigationApply the vendor patch (23.2R1-S1-EVO or later for 23.2-EVO branch) to address the NULL pointer handling during MAC learning when interface flaps occur.

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:= 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. Confirm Junos OS Evolved is running
    Run 'show version' or 'show system software' and verify the OS is 'Junos OS Evolved' rather than 'Junos OS'
    Affected if The device is running Junos OS Evolved (the vulnerability only affects the Evolved variant)
  2. Check installed version is 23.2
    Run 'show version' and look for version string containing '23.2' exactly. Compare against affected range = 23.2
    Affected if Version is exactly 23.2 (the vulnerability only affects this specific version)
  3. Verify Layer 2 bridging is configured
    Run 'show bridge domain' or 'show Layer 2 forwarding' to see if any Layer 2 domains or bridging instances exist
    Affected if Layer 2 bridging or VLANs are configured, enabling traffic to flow through logical interfaces
  4. Check for interface flap events
    Run 'show interface terse' repeatedly or review recent system logs for interface up/down events on logical interfaces. Also check 'show log messages' for flap-related entries
    Affected if Any logical interfaces are experiencing flaps or have recently flapped
  5. Monitor evo-aftmand-bt process behavior
    Run 'show system processes' or check if the evo-aftmand-bt process has recently restarted or is exhibiting unstable behavior
    Affected if The evo-aftmand-bt process is crashing or restarting repeatedly

A user is affected if the device runs Junos OS Evolved version 23.2 with Layer 2 bridging configured and has logical interfaces that are flapping or have recently flapped during MAC learning.

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

Apply the vendor patch (23.2R1-S1-EVO or later for 23.2-EVO branch) to address the NULL pointer handling during MAC learning when interface flaps occur.

Recommended fix High confidence

23.2R1-S1-EVO or 23.2R2-EVO

  1. Schedule a maintenance window for the upgrade procedure
  2. Backup the current Junos OS Evolved configuration
  3. Upgrade to Junos OS Evolved 23.2R1-S1-EVO or 23.2R2-EVO (or later)
  4. After reboot, verify theevo-aftmand-bt process is running normally
  5. Confirm PFE (Packet Forwarding Engine) is operational and no cores are generated

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
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,080
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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-2024-30403 in production — separate from our analysis above.

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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
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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  • No spam, self-promotion, credentials, or personal data