CVE-2026-77021

MEDIUM CVSS 4.0: 5.3
Updated Sep 21, 2026
Payload
Parameter Value
CVSS 5.3 (MEDIUM)
Type CWE-409
Vendor Payload
Public PoC No

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.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
Low
Basic privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
None
No data leak
Integrity
None
No data modification
Availability
Low
Partial disruption

CVSS Vector v4.0

Weakness Type (CWE)