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JunosOperating system · Juniper

CVE-2020-1647

CRITICAL · 9.8 CVSS v3.1 Published 2020-07-17
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
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
On Juniper Networks SRX Series with ICAP (Internet Content Adaptation Protocol) redirect service enabled, a double free vulnerability can lead to a Denial of Service (DoS) or Remote Code Execution (RCE) due to processing of a specific HTTP message. Continued processing of this specific HTTP message may result in an extended Denial of Service (DoS). The offending HTTP message that causes this issue may originate both from the HTTP server or the client. This issue affects Juniper Networks Junos OS on SRX Series: 18.1 versions prior to 18.1R3-S9; 18.2 versions prior to 18.2R3-S3; 18.3 versions prior to 18.3R2-S4, 18.3R3-S1; 18.4 versions prior to 18.4R2-S5, 18.4R3; 19.1 versions prior to 19.1R2; 19.2 versions prior to 19.2R1-S2, 19.2R2; 19.3 versions prior to 19.3R2. This issue does not affect Juniper Networks Junos OS prior to 18.1R1.

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 double free vulnerability exists in Juniper SRX Series firewalls when ICAP redirect service is enabled. Processing a specific HTTP message (from either server or client) triggers the double free, leading to potential Denial of Service or Remote Code Execution.

MitigationUpgrade Junos OS to the specified patched versions (18.1R3-S9, 18.2R3-S3, 18.3R2-S4/18.3R3-S1, 18.4R2-S5/18.4R3, 19.1R2, 19.2R1-S2/19.2R2, or 19.3R2 or later). If upgrading is not immediately feasible, consider disabling ICAP redirect service if not required.

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:= 18.1= 18.2= 18.3= 18.4= 19.1= 19.2= 19.3

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
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 'show system information' to confirm the device is a Juniper SRX Series firewall
    Affected if Device is not an SRX Series model, then not affected by this specific vulnerability
  2. Check Junos OS version
    Run 'show version' to obtain the installed Junos OS version number
    Affected if Version matches 18.1, 18.2, 18.3, 18.4, 19.1, 19.2, or 19.3 (any patch level) - these are the affected ranges
  3. Verify ICAP redirect service configuration
    Run 'show configuration | display set | match icap' or 'show servicesicap' to examine whether ICAP redirect service is configured and enabled
    Affected if ICAP redirect service is actively configured on the device

The device is affected if it is an SRX Series firewall running Junos version 18.1 through 19.3 AND has ICAP redirect service enabled.

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 patched versions (18.1R3-S9, 18.2R3-S3, 18.3R2-S4/18.3R3-S1, 18.4R2-S5/18.4R3, 19.1R2, 19.2R1-S2/19.2R2, or 19.3R2 or later). If upgrading is not immediately feasible, consider disabling ICAP redirect service if not required.

Recommended fix High confidence

18.1R3-S9 / 18.2R3-S3 / 18.3R2-S4 / 18.3R3-S1 / 18.4R2-S5 / 18.4R3 / 19.1R2 / 19.2R1-S2 / 19.2R2 / 19.3R2 (depending on starting branch)

  1. 1. Identify the current Junos OS version running on the SRX Series device using 'show version'
  2. 2. Identify which version branch you are on (18.1, 18.2, 18.3, 18.4, 19.1, 19.2, or 19.3)
  3. 3. If on 18.1 branch, upgrade to 18.1R3-S9 or later
  4. 4. If on 18.2 branch, upgrade to 18.2R3-S3 or later
  5. 5. If on 18.3 branch, upgrade to 18.3R2-S4 or 18.3R3-S1 or later
  6. 6. If on 18.4 branch, upgrade to 18.4R2-S5 or 18.4R3 or later
  7. 7. If on 19.1 branch, upgrade to 19.1R2 or later
  8. 8. If on 19.2 branch, upgrade to 19.2R1-S2 or 19.2R2 or later
Caveat Standard Junos upgrade considerations apply - review release notes for compatibility, ensure configuration compatibility, and plan for potential downtime

Generated from the published advisory — verify against the referenced sources before acting.

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-2020-1647 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
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data