CVE-2026-77021

mediumpriority · track · 0EPSS 0.004 · 32 %ileDE

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

0.38% (32nd) EPSS

CVSS 5.3 · medium

Is it mine?

5 products

Check your exposure

Who says so?

1 sources

cert_bund

EPSS · scored 2026-10-27

Improper handling of highly compressed data (data amplification) in Checkmk <2.5.0p14, <2.4.0p37, <2.3.0p51 and 2.2.0 (EOL) allows an attacker who controls a host registered for push mode to exhaust the memory of the agent receiver by sending a small zlib compressed payload that decompresses to an arbitrary size.

cvss

Technical severity, 0–10. One row per scoring source.

5.3

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–medium · 1.3–5.3

v4.05.3mediumCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Xsecondary · security@checkmk.com

v4.01.3lowCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Xsecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Trackcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-409US

affected products (5)

Products and version ranges known to be affected.

Checkmk Checkmk 2.2.0all versionscert_bundDEcpe:/a:checkmk:checkmk:2.2.0
Checkmk Checkmk 2.3.0all versionscert_bundDEcpe:/a:checkmk:checkmk:2.3.0
Checkmk Checkmk 2.4.0all versionscert_bundDEcpe:/a:checkmk:checkmk:2.4.0
Checkmk Checkmk <2.5.0p12all versionscert_bundDE
Checkmk Checkmk< 2.5.0p12cert_bundDE

advisories (1)

Vendor and ecosystem advisories describing this.

WID-SEC-W-2026-3192Checkmk: Schwachstelle ermöglicht Denial of ServiceDeutsch2026-09-03csaf · cert_bundDE
Ein entfernter, authentisierter Angreifer kann eine Schwachstelle in Checkmk Agent Receiver ausnutzen, um einen Denial of Service Angriff durchzuführen.

sources

Which sources assert this record, and when.

cert_bund NVD CVE.org MITRE

published 2026-09-21modified 2026-09-21

references (1) nvd

External citations — patches, advisories, analysis.

https://checkmk.com/werk/22116

scry

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