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FlussApplication · Apache

CVE-2026-49361

HIGH · 7.5 CVSS v3.1 Published 2026-06-01
Fix available
A fix is available. Upgrade to 0.9.1 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
Apache Fluss versions prior to 0.9.1 configure the Netty LengthFieldBasedFrameDecoder with Integer.MAX_VALUE as the maximum frame length, allowing unauthenticated remote attackers to exhaust JVM heap memory on TabletServer and CoordinatorServer by sending specially crafted frame headers, resulting in denial of service. This issue affects Apache Fluss (incubating): 0.8.0 and 0.9.0. Users are recommended to upgrade to version 0.9.1, which fixes the issue.

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

Apache Fluss versions 0.8.0 and 0.9.0 configure Netty's LengthFieldBasedFrameDecoder with Integer.MAX_VALUE as the maximum frame length. An unauthenticated remote attacker can send specially crafted frame headers claiming extremely large frame sizes, causing the JVM to attempt heap allocation based on the attacker-specified length, resulting in heap exhaustion and denial of service on both TabletServer and CoordinatorServer.

MitigationUpgrade to Apache Fluss version 0.9.1, which fixes this vulnerability by implementing a reasonable maximum frame length limit instead of using Integer.MAX_VALUE.

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
FlussApplication
Affected:>= 0.8.0, < 0.9.1

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 installed Apache Fluss version
    Locate the Fluss installation and check its version file or JAR manifest, or run 'fluss --version' if available
    Affected if Version is 0.8.0 through 0.9.0 (inclusive)
  2. Confirm TabletServer is running
    Check running processes for the TabletServer component using process listing commands (ps, jps, or similar)
    Affected if TabletServer process is active on the system
  3. Confirm CoordinatorServer is running
    Check running processes for the CoordinatorServer component using process listing commands (ps, jps, or similar)
    Affected if CoordinatorServer process is active on the system
  4. Inspect Netty frame decoder configuration
    Examine the Netty pipeline configuration for LengthFieldBasedFrameDecoder settings, specifically the maxFrameLength parameter
    Affected if maxFrameLength is set to Integer.MAX_VALUE (2147483647) or an equivalent unrestricted value

The environment is affected if Apache Fluss version 0.8.0 through 0.9.0 is installed and either TabletServer or CoordinatorServer is running with the default unrestricted Netty frame length configuration.

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 0.9.1 or later
Fixed in 0.9.1
Interim mitigation

Upgrade to Apache Fluss version 0.9.1, which fixes this vulnerability by implementing a reasonable maximum frame length limit instead of using Integer.MAX_VALUE.

Recommended fix High confidence

0.9.1

  1. 1. Stop all running Fluss TabletServer and CoordinatorServer services
  2. 2. Upgrade Apache Fluss from version 0.8.0 or 0.9.0 to version 0.9.1
  3. 3. Verify the Netty configuration in the upgraded version uses a properly bounded maximum frame length instead of Integer.MAX_VALUE
  4. 4. Restart the TabletServer and CoordinatorServer services

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

Fix this in Fluss Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,720
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An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,752.

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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-2026-49361 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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  • No spam, self-promotion, credentials, or personal data