CVE-2026-90990

Summary

Improper neutralization of newlines in filter values in the monitoring host and service list APIs in Checkmk <2.5.0p14 allows an authenticated user to inject additional Livestatus query headers, bypassing object visibility restrictions in count queries to infer information about hosts and services outside their contact groups and occupying web server and Livestatus workers for an attacker-controlled duration.

Affected Software

VendorProductVersion RangeStatus
Checkmk GmbHCheckmk2.5.0 < 2.5.0p14affected

Weaknesses

  • CWE-93: CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection')

ADP Enrichment

CISA ADP Vulnrichment

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

References