JunosOperating system · Juniper

CVE-2019-0051

HIGH · 7.5 CVSS v3.1 Published 2019-10-09
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
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
SSL-Proxy feature on SRX devices fails to handle a hardware resource limitation which can be exploited by remote SSL/TLS servers to crash the flowd daemon. Repeated crashes of the flowd daemon can result in an extended denial of service condition. For this issue to occur, clients protected by the SRX device must initiate a connection to the malicious server. This issue affects: Juniper Networks Junos OS on SRX5000 Series: 12.3X48 versions prior to 12.3X48-D85; 15.1X49 versions prior to 15.1X49-D180; 17.3 versions prior to 17.3R3-S7; 17.4 versions prior to 17.4R2-S6, 17.4R3; 18.1 versions prior to 18.1R3-S8; 18.2 versions prior to 18.2R3; 18.3 versions prior to 18.3R2; 18.4 versions prior to 18.4R2; 19.1 versions prior to 19.1R2.

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

The SSL-Proxy feature on Juniper SRX5000 Series devices fails to properly handle a hardware resource limitation when clients behind the SRX initiate connections to malicious SSL/TLS servers. This causes the flowd daemon to crash, and repeated crashes can result in an extended denial of service condition.

MitigationUpgrade Junos OS to the fixed versions (12.3X48-D85, 15.1X49-D180, 17.3R3-S7, 17.4R2-S6/17.4R3, 18.1R3-S8, 18.2R3, 18.3R2, 18.4R2, or 19.1R2). As a workaround, consider disabling SSL-Proxy for outbound connections or implementing traffic filtering to block suspicious server responses.

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:= 12.3x48= 15.1x49= 17.3= 17.4= 18.1= 18.2= 18.3= 18.4= 19.1

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
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 device model to confirm it is an SRX5000 Series device (SRX5400, SRX5600, or SRX5800)
    Affected if Device is an SRX5000 Series model
  2. Check Junos version
    Run 'show version' to obtain the installed Junos OS version
    Affected if Version matches any of the affected releases: 12.3X48, 15.1X49, 17.3, 17.4, 18.1, 18.2, 18.3, 18.4, or 19.1 (without the fixed maintenance updates)
  3. Verify SSL-Proxy is enabled
    Run 'show services ssl-proxy status' or 'show configuration services ssl-proxy' to check if SSL-Proxy feature is configured and active
    Affected if SSL-Proxy is enabled for outbound proxy operations
  4. Check for flowd daemon crashes
    Run 'show log messages' and search for 'flowd' crash entries, or use 'request support information' and look for flowd core dumps in /var/crash/
    Affected if flowd daemon crashes are present in logs or core dumps exist

Device is affected if it is an SRX5000 Series running an affected Junos version with SSL-Proxy enabled, and flowd crashes have occurred.

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 (12.3X48-D85, 15.1X49-D180, 17.3R3-S7, 17.4R2-S6/17.4R3, 18.1R3-S8, 18.2R3, 18.3R2, 18.4R2, or 19.1R2). As a workaround, consider disabling SSL-Proxy for outbound connections or implementing traffic filtering to block suspicious server responses.

Fix this in Junos Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
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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-2019-0051 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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