CVE-2026-77021

EUVD-2026-83883
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.
Data Amplification
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
CheckmkCNA
5.3 MEDIUM
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
checkmkcheckmk
2.5.0 ≤
𝑥
≤ 2.5.0p13
CNA
checkmkcheckmk
2.4.0 ≤
𝑥
≤ 2.4.0p36
CNA
checkmkcheckmk
2.3.0 ≤
𝑥
≤ 2.3.0p50
CNA
checkmkcheckmk
2.2.0
CNA
Common Weakness Enumeration
References
https://checkmk.com/werk/22116