CVE-2026-44838: RabbitMQ is a messaging and streaming broker

Routine

HIGH 8.1UPGRADE

CVE-2026-44838 is a high-severity flaw (CVSS 8.1) affecting rabbitmq server. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

RabbitMQ is a messaging and streaming broker. From 4.2.0 to before 4.2.4, RabbitMQ's MQTT plugin allows for topic-level authorization using regular expressions with variable substitution. Administrators can create patterns such as ^{client_id}-sensors$ to restrict user access to topics that include their client ID. However, the client_id is provided by the user in the MQTT CONNECT packet and is inserted into the regex pattern without escaping spe

Why this priority

High severity

A fixed release or distro patch exists.

Risk facts

CVSS score	8.1 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.2% (top 90%)
CISA exploited list	No
Weakness	CWE-863
Published	2026-05-27
Last modified	2026-10-26

Publisher (CNA): GitHub, Inc. · Vendor: broadcom

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-27 15:16 UTCPublished CVE record published
2026-10-26 11:10 UTCUpdated Record last modified

broadcom rabbitmq server UPGRADE

Affected: >= 4.2.0 and < 4.2.4

Fixed in: 4.2.4

Safe to downgrade to: a release before 4.2.0

1. Check installed version

apt-cache policy rabbitmq-server || rpm -q rabbitmq-server || rabbitmq-server --version

2. UPGRADE to 4.2.4 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade rabbitmq-server

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade rabbitmq-server

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 4.2.0 (Debian / Ubuntu)

apt-cache madison rabbitmq-server sudo apt install rabbitmq-server=<VERSION_BEFORE_4.2.0> sudo apt-mark hold rabbitmq-server

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

dnf --showduplicates list rabbitmq-server sudo dnf downgrade rabbitmq-server-<VERSION_BEFORE_4.2.0> sudo dnf versionlock add rabbitmq-server

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-2026-44838?

rabbitmq server: upgrade to 4.2.4. Exact commands for each OS are on this page.

Is CVE-2026-44838 being exploited?

CVE-2026-44838 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-2026-44838 affect?

CVE-2026-44838 affects rabbitmq server. Severity is high (CVSS 8.1). RabbitMQ is a messaging and streaming broker. From 4.2.0 to before 4.2.4, RabbitMQ's MQTT plugin allows for topic-level authorization using regular expressions with variable substitution. Administrators can create patterns such as ^{client_

How urgent is CVE-2026-44838?

Priority 31/100. High severity

Software pages

RabbitMQ vulnerabilities

Related CVEs

CVE-2026-44839 MEDIUM 4.8 UPGRADE RabbitMQ is a messaging and streaming broker
CVE-2026-57219 HIGH 7.5 UPGRADE RabbitMQ is a messaging and streaming broker
CVE-2026-57220 HIGH 7.5 UPGRADE RabbitMQ is a messaging and streaming broker
CVE-2026-57211 MEDIUM 6.5 UPGRADE RabbitMQ is a messaging and streaming broker
CVE-2026-57215 HIGH 8.8 UPGRADE RabbitMQ is a messaging and streaming broker

References

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