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Rocket.chatApplication

CVE-2023-28356

HIGH · 7.5 CVSS v3.1 Published 2023-05-11
Fix available
A fix is available. Upgrade to 6.0.0 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 vulnerability has been identified where a maliciously crafted message containing a specific chain of characters can cause the chat to enter a hot loop on one of the processes, consuming ~120% CPU and rendering the service unresponsive.

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 · moderate confidence

A denial-of-service vulnerability in the chat service where a specially crafted message containing a specific character sequence triggers an infinite loop in one of the processes, causing ~120% CPU utilization and rendering the service unresponsive.

MitigationImplement input validation to detect and sanitize the specific malicious character chain before processing, and/or fix the code logic that causes the infinite loop when processing this input.

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
Rocket.chatApplication
Affected:< 6.0.0

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 Rocket.chat version
    Run 'rocketchatctl version' or check the package.json file in the Rocket.chat installation directory, or access the admin panel and navigate to 'Administration > Info' to view the version number
    Affected if The installed version is below 6.0.0
  2. Confirm chat service is running
    Check if the Rocket.chat service process is active using 'systemctl status rocketchat' or 'service rocketchat status' depending on your system
    Affected if The service is running and exposed to network traffic
  3. Monitor CPU utilization of chat processes
    Use 'top' or 'htop' to observe CPU usage of Rocket.chat processes, specifically look for any process consuming ~120% CPU consistently
    Affected if A Rocket.chat process is showing approximately 120% CPU utilization, indicating the infinite loop is occurring
  4. Inspect incoming chat messages for trigger sequence
    Review application logs at '/var/log/rocketchat/server.log' or equivalent log location, searching for the specific character sequence that triggers the vulnerability
    Affected if Log entries show receipt of the malicious character sequence preceding service degradation
  5. Check for service unresponsiveness
    Attempt to access the Rocket.chat web interface and send a test message, or check if API endpoints return timeout errors
    Affected if The service fails to respond to chat requests or shows significant latency

You are affected if Rocket.chat version is below 6.0.0 and you observe ~120% CPU usage in chat processes or have received specially crafted messages containing the trigger character sequence.

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 6.0.0 or later
Fixed in 6.0.0
Interim mitigation

Implement input validation to detect and sanitize the specific malicious character chain before processing, and/or fix the code logic that causes the infinite loop when processing this input.

Recommended fix Moderate confidence

6.0.0 or later

  1. Backup your Rocket.chat database and configuration files before upgrading
  2. Review Rocket.chat 6.0.0 release notes for any migration requirements or prerequisites
  3. Ensure your system meets the requirements for version 6.0.0 (MongoDB and Node.js version compatibility)
  4. Stop the Rocket.chat service
  5. Upgrade Rocket.chat to version 6.0.0 or later using your package manager or installation method
  6. Start the Rocket.chat service after upgrade
  7. Verify the service is running correctly and the hot loop vulnerability is resolved
Caveat Review 6.0.0 release notes for breaking changes, particularly MongoDB version requirements and any API changes

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

Fix this in Rocket.chat Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
Get the upgrade done

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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-2023-28356 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