CVE-2026-90990 Details
Description
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.
A vulnerability exists in Checkmk versions through 2.5.0p14, allowing authenticated users to inject additional Livestatus query headers via the monitoring host and service list APIs. This injection bypasses object visibility restrictions in count queries, enabling users to infer information about hosts and services outside their contact groups. Additionally, the injection can occupy web server and Livestatus workers for a duration controlled by the attacker.
Users can upgrade to Checkmk versions 2.5.0p15 or 3.0.0b1 to address this vulnerability.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Sep 22, 2026CISA-ADP
Assessed Sep 22, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://checkmk.com/werk/19604 | [email protected] | AdvisoryRemedyVendor |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-93 | Improper Neutralization of CRLF Sequences ('CRLF Injection') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| Checkmk | >= 2.5.0, < 2.5.0p14 |
CPE
Remediation
| |
Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Sep 22, 2026 | CVE Modified | CISA-ADP |
| Sep 22, 2026 | New CVE Received | [email protected] |