Livestatus injection via monitoring filter values (CVE-2026-90990) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-90990

Livestatus injection via monitoring filter values

Answer in brief

CVE-2026-90990 records a Unknown severity vulnerability in Livestatus injection via monitoring filter values. The current sources do not mark it as known exploited. The current feed maps Checkmk GmbH/Checkmk (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 22, 2026Updated Sep 22, 2026Source checked Sep 22, 2026First seen by HOL Sep 22, 2026Material review Sep 22, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Checkmk GmbH/Checkmk (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Checkmk GmbH/Checkmkgeneric	>=2.5.0 <2.5.0p14	2.5.0p14

Recommended response

Check inventory. Check lockfiles and deployed manifests for Checkmk GmbH/Checkmk.
Review the reported fix. Update Checkmk GmbH/Checkmk to 2.5.0p14 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 22, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 22, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 22, 2026

Sources and claim methodology

Source referencecheckmk.com

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.