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JunosOperating system · Juniper

CVE-2017-2346

MEDIUM · 5.9 CVSS v3.0 Published 2017-07-17
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
68/100
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 MS-MPC or MS-MIC Service PIC may crash when large fragmented packets are passed through an Application Layer Gateway (ALG). Repeated crashes of the Service PC can result in an extended denial of service condition. The issue can be seen only if NAT or stateful-firewall rules are configured with ALGs enabled. This issue was caused by the code change for PR 1182910 in Junos OS 14.1X55-D30, 14.1X55-D35, 14.2R7, 15.1R5, and 16.1R2. No other versions of Junos OS and no other Juniper Networks products or platforms are affected by this issue. Affected releases are Juniper Networks Junos OS on MX platforms running: 14.1X55 from 14.1X55-D30 to releases prior to 14.1X55-D35; 14.2R from 14.2R7 to releases prior to 14.2R7-S4, 14.2R8; 15.1R from 15.1R5 to releases prior to 15.1R5-S2, 15.1R6; 16.1R from 16.1R2 to releases prior to 16.1R3-S2, 16.1R4.

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

On Juniper MX platforms running vulnerable Junos OS versions, the MS-MPC or MS-MIC Service PIC crashes when large fragmented packets traverse an Application Layer Gateway (ALG) configured with NAT or stateful-firewall rules. The vulnerability was introduced by code change PR 1182910 and leads to extended denial of service through repeated Service PIC crashes.

MitigationUpgrade Junos OS to the fixed versions: 14.1X55-D35 or later, 14.2R7-S4/14.2R8 or later, 15.1R5-S2/15.1R6 or later, or 16.1R3-S2/16.1R4 or later. As a temporary workaround, consider disabling ALGs if operationally 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:= 14.1x55= 14.2= 15.1= 16.1

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
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.0/AV:N/AC:H/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. Verify Juniper MX platform
    Run 'show chassis hardware' or 'show system information' to confirm the device is an MX series router
    Affected if Only MX platforms are affected; other Juniper product lines are not vulnerable to this CVE
  2. Check Junos OS version
    Run 'show version' to obtain the installed Junos OS version
    Affected if Version 14.1x55, 14.2, 15.1, or 16.1 is installed and falls within the affected range before the fixed releases (14.1X55-D35, 14.2R7-S4/14.2R8, 15.1R5-S2/15.1R6, 16.1R3-S2/16.1R4)
  3. Confirm MS-MPC or MS-MIC Service PIC presence
    Run 'show chassis hardware' and look for MS-MPC or MS-MIC line cards or PICs in the hardware inventory
    Affected if The device has an MS-MPC or MS-MIC Service PIC installed; without this hardware, the vulnerability cannot be triggered
  4. Identify active ALG configuration with NAT or stateful firewall
    Run 'show configuration | match alg' and 'show configuration | display set | match nat' or 'show configuration | display set | match stateful-firewall' to locate ALG-enabled NAT or stateful-firewall rules in the configuration
    Affected if An ALG is configured with NAT or stateful-firewall rules; the vulnerability only triggers when large fragmented packets traverse such ALG configurations

A user is affected if they are on an MX platform running a vulnerable Junos version (14.1x55, 14.2, 15.1, or 16.1), have an MS-MPC or MS-MIC Service PIC installed, and have an ALG configured with active NAT or stateful-firewall rules processing traffic.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade Junos OS to the fixed versions: 14.1X55-D35 or later, 14.2R7-S4/14.2R8 or later, 15.1R5-S2/15.1R6 or later, or 16.1R3-S2/16.1R4 or later. As a temporary workaround, consider disabling ALGs if operationally feasible.

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
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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-2017-2346 in production — separate from our analysis above.

No notes yet

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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
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data