CVE-2026-34584: listmonk is a standalone, self-hosted, newsletter and mailing list manager

Routine

MEDIUM 5.4UPGRADE

CVE-2026-34584 is a medium-severity flaw (CVSS 5.4) affecting listmonk. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

listmonk is a standalone, self-hosted, newsletter and mailing list manager. From version 4.1.0 to before version 6.1.0, bugs in list permission checks allows users in a multi-user environment to access to lists (which they don't have access to) under different scenarios. This only affects multi-user environments with untrusted users. This issue has been patched in version 6.1.0.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	5.4 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.2% (top 93%)
CISA exploited list	No
Weakness	CWE-639
Published	2026-04-02
Last modified	2026-07-24

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

Last updated 2026-07-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-02 18:16 UTCPublished CVE record published
2026-07-24 21:10 UTCUpdated Record last modified

nadh listmonk UPGRADE

Affected: >= 4.1.0 and < 6.1.0

Fixed in: 6.1.0

Safe to downgrade to: a release before 4.1.0

1. Check installed version

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

2. UPGRADE to 6.1.0 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade listmonk

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 4.1.0 (Debian / Ubuntu)

apt-cache madison listmonk sudo apt install listmonk=<VERSION_BEFORE_4.1.0> sudo apt-mark hold listmonk

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

dnf --showduplicates list listmonk sudo dnf downgrade listmonk-<VERSION_BEFORE_4.1.0> sudo dnf versionlock add listmonk

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-2026-34584?

listmonk: upgrade to 6.1.0. Exact commands for each OS are on this page.

Is CVE-2026-34584 being exploited?

CVE-2026-34584 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-2026-34584 affect?

CVE-2026-34584 affects listmonk. Severity is medium (CVSS 5.4). listmonk is a standalone, self-hosted, newsletter and mailing list manager. From version 4.1.0 to before version 6.1.0, bugs in list permission checks allows users in a multi-user environment to access to lists (which they don't have access

How urgent is CVE-2026-34584?

Priority 21/100. No elevated risk signals yet.

Related CVEs

CVE-2026-34828 HIGH 7.1 UPGRADE listmonk is a standalone, self-hosted, newsletter and mailing list manager

References

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