CVE-2026-49361: Apache Fluss versions prior to 0.9.1 configure the Netty LengthFieldBasedFrameDecoder with Integer.MAX_VALUE a

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HIGH 7.5REMOTEWATCHLISTUPGRADE

CVE-2026-49361 is a high-severity flaw (CVSS 7.5) affecting fluss. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 t

Why this priority

High severity
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.8% (top 43%)
CISA exploited list	No
Weakness	CWE-400, CWE-770
Published	2026-06-01
Last modified	2026-07-22

Publisher (CNA): Apache Software Foundation · Vendor: apache

Last updated 2026-07-22 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-01 09:16 UTCPublished CVE record published
2026-07-22 07:10 UTCUpdated Record last modified

apache fluss UPGRADE

Affected: >= 0.8.0 and < 0.9.1

Fixed in: 0.9.1

Safe to downgrade to: a release before 0.8.0

1. Check installed version

apt-cache policy fluss || rpm -q fluss || fluss --version

2. UPGRADE to 0.9.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade fluss

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade fluss

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 0.8.0 (Debian / Ubuntu)

apt-cache madison fluss sudo apt install fluss=<VERSION_BEFORE_0.8.0> sudo apt-mark hold fluss

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list fluss sudo dnf downgrade fluss-<VERSION_BEFORE_0.8.0> sudo dnf versionlock add fluss

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-49361?

fluss: upgrade to 0.9.1. Exact commands for each OS are on this page.

Is CVE-2026-49361 being exploited?

CVE-2026-49361 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-49361 affect?

CVE-2026-49361 affects fluss. Severity is high (CVSS 7.5). 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 CoordinatorSe

How urgent is CVE-2026-49361?

Priority 51/100. High severity; Remotely exploitable, no login, no user action; On your watchlist

References

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