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JunosOperating system · Juniper

CVE-2026-33787

MEDIUM · 5.5 CVSS v3.1 Published 2026-04-09
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
57/100
Remediation priority · Elevated
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 Improper Check for Unusual or Exceptional Conditions vulnerability in the chassis control daemon (chassisd) of Juniper Networks Junos OS on SRX1500, SRX4100, SRX4200 and SRX4600 allows a local attacker with low privileges to cause a complete Denial of Service (DoS). When a specific 'show chassis' CLI command is executed, chassisd crashes and restarts which causes a momentary impact to all traffic until all modules are online again. This issue affects Junos OS on SRX1500, SRX4100, SRX4200 and SRX4600:  * 23.2 versions before 23.2R2-S6, * 23.4 versions before 23.4R2-S7 * 24.2 versions before 24.2R2-S2, * 24.4 versions before 24.4R2, * 25.2 versions before 25.2R1-S1, 25.2R2.

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 denial of service vulnerability exists in the chassis control daemon (chassisd) of Juniper Networks Junos OS on SRX1500, SRX4100, SRX4200, and SRX4600. A local attacker with low privileges can trigger daemon crash and restart by executing a specific 'show chassis' CLI command, causing momentary traffic disruption until modules reinitialize.

MitigationApply the vendor-supplied Junos OS updates: upgrade to 23.2R2-S6 or later, 23.4R2-S7 or later, 24.2R2-S2 or later, 24.4R2 or later, or 25.2R1-S1/25.2R2 or later depending on the current branch.

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:= 23.2= 23.4= 24.2= 24.4= 25.2

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
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/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 device model is affected hardware
    Execute 'show chassis hardware' or check the physical device labeling to verify the model is SRX1500, SRX4100, SRX4200, or SRX4600
    Affected if Device model is NOT one of these four SRX models
  2. Identify installed Junos OS version
    Execute 'show version' and note the Junos OS version number (for example, 23.2R1-S2, 24.4R1, etc.)
    Affected if Version matches or falls within the affected branches: 23.2.x, 23.4.x, 24.2.x, 24.4.x, or 25.2.x
  3. Verify chassis control daemon is running
    Execute 'show system processes extensive | match chassisd' to confirm the chassisd process is active
    Affected if The chassisd process is running (this is the default operational state)

Device is affected if it is an SRX1500/SRX4100/SRX4200/SRX4600 running Junos OS version 23.2, 23.4, 24.2, 24.4, or 25.2 (or any sub-version within these branches), as the vulnerable chassisd daemon will crash when the 'show chassis' command is executed.

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-supplied Junos OS updates: upgrade to 23.2R2-S6 or later, 23.4R2-S7 or later, 24.2R2-S2 or later, 24.4R2 or later, or 25.2R1-S1/25.2R2 or later depending on the current branch.

Recommended fix High confidence

23.2R2-S6, 23.4R2-S7, 24.2R2-S2, 24.4R2, 25.2R1-S1, or 25.2R2 (select based on your release train)

  1. 1. Identify the current Junos OS version on the affected SRX devices (SRX1500, SRX4100, SRX4200, SRX4600) using: show version
  2. 2. Download the appropriate fixed Junos OS release for your hardware platform: 23.2R2-S6 or later, 23.4R2-S7 or later, 24.2R2-S2 or later, 24.4R2 or later, or 25.2R1-S1/25.2R2 or later
  3. 3. Upload the new Junos OS image to the device using: file copy /path/to/junos-image.tgz /var/tmp/
  4. 4. Install the new image using: request system software add /var/tmp/junos-image.tgz reboot
  5. 5. After reboot, verify the new version is installed: show version and confirm chassisd is running: show chassis routing-engine
  6. 6. Test that the 'show chassis' command executes without crashing chassisd
Caveat Standard Junos upgrade considerations apply - review release notes for any migration steps and ensure configuration compatibility before upgrading

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

Fix this in Junos Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
13.0 hours of engineering $2,330
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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-2026-33787 in production — separate from our analysis above.

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What this is

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