CVE-2026-90579Public exploitNetwork attack vectorHinoki check available

Unauthenticated cross-user data access via trusted header

Published Sep 13, 2026 · Updated Sep 13, 2026

Missing authentication in Cheshire Cat AI 1.9.0 through 1.9.2 allows remote attackers to read or write any user's data via HTTP requests. The _authorize_http_key method accepts the client-controlled user_id header as the authenticated identity and returns full permissions when no API key is configured. A default, network-accessible deployment requires no credentials, exposing conversation history, episodic memory, and other per-user API data.

CVSS severityUnavailable
Unscored
EPSS probability0.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Missing authentication in Cheshire Cat AI 1.9.0 through 1.9.2 allows remote attackers to read or write any user's data via HTTP requests. The _authorize_http_key method accepts the client-controlled user_id header as the authenticated identity and returns full permissions when no API key is configured. A default, network-accessible deployment requires no credentials, exposing conversation history, episodic memory, and other per-user API data.

The record

CVE
CVE-2026-90579
Published
Sep 13, 2026
Updated
Sep 13, 2026
Vendor
Cheshire Cat AI
Product
Cheshire Cat AI
Classifications
T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 13, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 13, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.9.0
  2. Affected versionversion=1.9.1
  3. Affected versionversion=1.9.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Cheshire Cat AI · Cheshire Cat AIversion=1.9.0; version=1.9.1; version=1.9.2

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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