CVE-2026-33455: Livestatus injection in the monitoring quicksearch in Checkmk <2.5.0b4 allows an authenticated attacker to inj

Q: How urgent is CVE-2026-33455?

Priority 24/100. No elevated risk signals yet.

Routine

MEDIUM 6.3DOWNGRADE

CVE-2026-33455 is a medium-severity flaw (CVSS 6.3) affecting checkmk. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Livestatus injection in the monitoring quicksearch in Checkmk <2.5.0b4 allows an authenticated attacker to inject livestatus commands via the search query due to insufficient input sanitization in search filter plugins.

Why this priority

No elevated risk signals yet

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	6.3 (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-140
Published	2026-04-10
Last modified	2026-10-26

Publisher (CNA): Checkmk GmbH · Vendor: checkmk

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

Am I affected?

Timeline

2026-04-10 09:16 UTCPublished CVE record published
2026-10-26 00:10 UTCUpdated Record last modified

checkmk checkmk DOWNGRADE

Affected: 2.5.0 b1 · 2.5.0 b2 · 2.5.0 b3

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.5.0

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 2.5.0 (Debian / Ubuntu)

apt-cache madison checkmk sudo apt install checkmk=<VERSION_BEFORE_2.5.0> sudo apt-mark hold checkmk

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list checkmk sudo dnf downgrade checkmk-<VERSION_BEFORE_2.5.0> sudo dnf versionlock add checkmk

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-2026-33455?

checkmk: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-33455 being exploited?

CVE-2026-33455 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-2026-33455 affect?

CVE-2026-33455 affects checkmk. Severity is medium (CVSS 6.3). Livestatus injection in the monitoring quicksearch in Checkmk <2.5.0b4 allows an authenticated attacker to inject livestatus commands via the search query due to insufficient input sanitization in search filter plugins.

How urgent is CVE-2026-33455?

Priority 24/100. No elevated risk signals yet.

Related CVEs

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CVE-2024-47091 HIGH 7.8 DOWNGRADE Privilege escalation in the mk_mysql agent plugin on Windows in Checkmk <2.4.0p29, <2.3.0p47, and 2.2.0 (EOL)
CVE-2026-33456 HIGH 7.6 DOWNGRADE Livestatus injection in the notification test mode in Checkmk <2.5.0b4 and <2.4.0p26 allows an authenticated u
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References

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