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JunosOperating system · Juniper

CVE-2024-30392

HIGH · 7.5 CVSS v3.1 Published 2024-04-12
Fix available
A fix is available. Upgrade to 21.2 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 Stack-based Buffer Overflow vulnerability in Flow Processing Daemon (flowd) of Juniper Networks Junos OS allows an unauthenticated, network-based attacker to cause Denial of Service (DoS). On all Junos OS MX Series platforms with SPC3 and MS-MPC/-MIC, when URL filtering is enabled and a specific URL request is received and processed, flowd will crash and restart. Continuous reception of the specific URL request will lead to a sustained Denial of Service (DoS) condition. This issue affects: Junos OS: * all versions before 21.2R3-S6, * from 21.3 before 21.3R3-S5, * from 21.4 before 21.4R3-S5, * from 22.1 before 22.1R3-S3, * from 22.2 before 22.2R3-S1, * from 22.3 before 22.3R2-S2, 22.3R3, * from 22.4 before 22.4R2-S1, 22.4R3.

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 stack-based buffer overflow in the Flow Processing Daemon (flowd) on Juniper Junos OS MX Series with SPC3 and MS-MPC/-MIC allows an unauthenticated network attacker to cause flowd to crash and restart by sending a specific URL request when URL filtering is enabled, resulting in denial of service.

MitigationUpgrade Junos OS to a patched version (21.2R3-S6, 21.3R3-S5, 21.4R3-S5, 22.1R3-S3, 22.2R3-S1, 22.3R2-S2/22.3R3, or 22.4R2-S1/22.4R3). As a workaround, consider disabling URL filtering if an immediate upgrade is not feasible.

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:< 21.2= 21.2= 21.3= 21.4= 22.1= 22.2= 22.3= 22.4

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
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. Check Junos OS version
    Run 'show version' or 'show system information' to identify the installed Junos OS version
    Affected if The version is 21.2, 21.3, 21.4, 22.1, 22.2, 22.3, 22.4, or any version below 21.2
  2. Confirm MX Series platform with SPC3 or MS-MPC/-MIC
    Run 'show chassis hardware' or 'show hardware' to identify the device model and line card types
    Affected if The device is an MX Series router equipped with SPC3, MS-MPC, or MS-MIC line cards
  3. Verify URL filtering is enabled
    Run 'show services url-filtering status' or check the URL filtering configuration under 'services url-filtering' in the configuration
    Affected if URL filtering is enabled and active on the device
  4. Confirm flowd daemon is running
    Run 'show system processes extensive | match flowd' or 'ps aux | grep flowd' to verify the Flow Processing Daemon is active
    Affected if The flowd process is running - this is the vulnerable component

A user is affected if they are running an affected Junos version (21.2-22.4) on an MX Series with SPC3/MS-MPC/-MIC hardware, AND URL filtering is enabled, allowing an attacker to trigger the buffer overflow and crash flowd via a crafted URL request.

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 21.2 or later
Fixed in 21.2
Interim mitigation

Upgrade Junos OS to a patched version (21.2R3-S6, 21.3R3-S5, 21.4R3-S5, 22.1R3-S3, 22.2R3-S1, 22.3R2-S2/22.3R3, or 22.4R2-S1/22.4R3). As a workaround, consider disabling URL filtering if an immediate upgrade is not feasible.

Recommended fix High confidence

Upgrade to Junos OS 21.2R3-S6, 21.3R3-S5, 21.4R3-S5, or later (recommended: 22.4R3)

  1. 1. Identify the current Junos OS version running on the MX Series device using 'show version'
  2. 2. Confirm URL filtering is enabled by checking the configuration with 'show configuration | match url-filter'
  3. 3. Download the appropriate fixed Junos OS release from Juniper Networks (21.2R3-S6, 21.3R3-S5, 21.4R3-S5, or later)
  4. 4. Upload the Junos OS upgrade package to the device using 'file copy' or USB transfer
  5. 5. Install the upgrade using 'request system software add <package-name> reboot'
  6. 6. After reboot, verify the new version is running with 'show version'
  7. 7. Confirm URL filtering functionality is restored with 'show services url-filter status'
  8. 8. Monitor flowd process stability using 'show system processes | match flowd'
Caveat Review Juniper Networks Junos OS upgrade guide for MX Series; ensure compatibility with SPC3/MS-MPC hardware and review any changes to URL filtering functionality

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-2024-30392 in production — separate from our analysis above.

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What this is

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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