CVE-2026-77021

Summary

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.

Affected Software

VendorProductVersion RangeStatus
Checkmk GmbHCheckmk2.5.0 < 2.5.0p14affected
Checkmk GmbHCheckmk2.4.0 < 2.4.0p37affected
Checkmk GmbHCheckmk2.3.0 < 2.3.0p51affected
Checkmk GmbHCheckmk2.2.0affected

Weaknesses

  • CWE-409: CWE-409: Improper Handling of Highly Compressed Data (Data Amplification)

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References