CVE-2026-45334: Panel auth bypass leaks admin

Q: Is CVE-2026-45334 actively exploited?

No confirmed active exploitation of CVE-2026-45334 has been reported, but organizations should still patch proactively.

Q: How to fix CVE-2026-45334?

1. Patch: upgrade getkirby/cms to ≥4.9.1 (Kirby 4.x branch) or ≥5.4.1 (Kirby 5.x branch). 2. Scope check: audit all files under site/blueprints/users/*.yml for any role configured with users.access: false or users.list: false — only those configurations are exposed. 3. Workaround if patching is delayed: temporarily disable content-locking or set all Panel roles to allow mutual user visibility until the patch is applied. 4. Detection: review Panel access logs for low-privilege role accounts receiving successful 200 responses from endpoints that include lock user payloads (look for repeated requests during active editing sessions from accounts not expected to view users). 5. Post-incident: if a low-privilege account may have been misused, treat all admin email addresses as potentially enumerated and consider phishing-awareness briefings for admin staff.

Q: What systems are affected by CVE-2026-45334?

This vulnerability affects the following AI/ML architecture patterns: CMS-backed AI content portals, AI governance documentation systems, ML model documentation pipelines, Web-based AI management interfaces.

Q: What is the CVSS score for CVE-2026-45334?

No CVSS score has been assigned yet.

CISO Take

Kirby CMS up to version 4.9.0 fails to enforce user-visibility permissions when returning content-lock payloads, allowing any authenticated low-privilege Panel user to silently harvest the email address and internal identifier of any administrator or editor who currently has content open for editing. With 469 downstream dependents and no public exploit code or KEV listing, opportunistic mass exploitation is unlikely today, but the harvested admin email addresses directly enable targeted spearphishing and credential-stuffing attacks against the Kirby installation or any external service where those admins reuse credentials — a low-noise, high-value reconnaissance primitive that leaves almost no forensic trace. Upgrade getkirby/cms to 4.9.1 or 5.4.1 immediately; installations where all Panel roles are already permitted to list each other are not affected and require no action.

Sources: GitHub Advisory NVD OpenSSF ATLAS

What is the risk?

Medium risk overall. Exploitation requires a pre-existing authenticated low-privilege account, which is a meaningful precondition, but once inside the Panel the attack is entirely passive — no writes, no anomalous payloads, just reading standard API responses. The default 10-minute content-lock window limits per-session exposure, but an attacker with persistent low-privilege access can poll continuously and enumerate all active admin accounts over time. No EPSS data is available and no public exploit exists, reducing near-term urgency, but the trivial post-authentication complexity and near-zero detection footprint warrant prompt patching rather than scheduled maintenance.

How does the attack unfold?

Initial Access

Attacker authenticates to Kirby Panel using a legitimately obtained low-privilege account belonging to a role configured with users.access: false or users.list: false.

AML.T0012

Exploitation

While a higher-privilege user has content open for editing (triggering a 10-minute content lock), the attacker makes standard Panel view requests that return lock payloads containing the locking user's identity without permission checks.

AML.T0049

Identity Harvesting

Attacker extracts admin email addresses and internal user IDs from unfiltered lock information across multiple editing sessions, building a complete enumeration of privileged accounts.

AML.T0087

Downstream Attack

Harvested admin emails are weaponized in targeted spearphishing campaigns or credential-stuffing attacks against the organization's AI infrastructure, cloud ML environments, or SaaS services.

AML.T0052

Initial Access

Attacker authenticates to Kirby Panel using a legitimately obtained low-privilege account belonging to a role configured with users.access: false or users.list: false.

AML.T0012

Exploitation

While a higher-privilege user has content open for editing (triggering a 10-minute content lock), the attacker makes standard Panel view requests that return lock payloads containing the locking user's identity without permission checks.

AML.T0049

Identity Harvesting

Attacker extracts admin email addresses and internal user IDs from unfiltered lock information across multiple editing sessions, building a complete enumeration of privileged accounts.

AML.T0087

Downstream Attack

Harvested admin emails are weaponized in targeted spearphishing campaigns or credential-stuffing attacks against the organization's AI infrastructure, cloud ML environments, or SaaS services.

AML.T0052

What systems are affected?

Package	Ecosystem	Vulnerable Range	Patched
Panel	composer	<= 4.9.0	`4.9.1`
5.8K OpenSSF 6.8 505 dependents Pushed 6d ago 68% patched ~15d to patch Full package profile →

Do you use Panel? You're affected.

How severe is it?

CVSS 3.1

N/A

EPSS

0.4%

chance of exploitation in 30 days

Higher than 28% of all CVEs

Source: EPSS v3 — FIRST.org

Exploitation Status

No known exploitation

Sophistication

Trivial

What should I do?

5 steps

Patch: upgrade getkirby/cms to ≥4.9.1 (Kirby 4.x branch) or ≥5.4.1 (Kirby 5.x branch).
Scope check: audit all files under site/blueprints/users/*.yml for any role configured with users.access: false or users.list: false — only those configurations are exposed.
Workaround if patching is delayed: temporarily disable content-locking or set all Panel roles to allow mutual user visibility until the patch is applied.
Detection: review Panel access logs for low-privilege role accounts receiving successful 200 responses from endpoints that include lock user payloads (look for repeated requests during active editing sessions from accounts not expected to view users).
Post-incident: if a low-privilege account may have been misused, treat all admin email addresses as potentially enumerated and consider phishing-awareness briefings for admin staff.

What does CISA's SSVC say?

Decision Track

Exploitation none

Automatable No

Technical Impact partial

Source: CISA Vulnrichment (SSVC v2.0). Decision based on the CISA Coordinator decision tree.

How is it classified?

Data Extraction Privacy Violation Auth Bypass Framework AML.T0012 - Valid Accounts AML.T0049 - Exploit Public-Facing Application AML.T0052 - Phishing AML.T0087 - Gather Victim Identity Information

Which compliance frameworks are affected?

This CVE is relevant to:

EU AI Act

Art. 15 - Accuracy, robustness and cybersecurity

ISO 42001

A.9.3 - AI system security

NIST AI RMF

GOVERN 6.2 - Policies and procedures for AI risk management

OWASP LLM Top 10

LLM02 - Sensitive Information Disclosure

Frequently Asked Questions

What is CVE-2026-45334?

Kirby CMS up to version 4.9.0 fails to enforce user-visibility permissions when returning content-lock payloads, allowing any authenticated low-privilege Panel user to silently harvest the email address and internal identifier of any administrator or editor who currently has content open for editing. With 469 downstream dependents and no public exploit code or KEV listing, opportunistic mass exploitation is unlikely today, but the harvested admin email addresses directly enable targeted spearphishing and credential-stuffing attacks against the Kirby installation or any external service where those admins reuse credentials — a low-noise, high-value reconnaissance primitive that leaves almost no forensic trace. Upgrade getkirby/cms to 4.9.1 or 5.4.1 immediately; installations where all Panel roles are already permitted to list each other are not affected and require no action.

Is CVE-2026-45334 actively exploited?

No confirmed active exploitation of CVE-2026-45334 has been reported, but organizations should still patch proactively.

How to fix CVE-2026-45334?

1. Patch: upgrade getkirby/cms to ≥4.9.1 (Kirby 4.x branch) or ≥5.4.1 (Kirby 5.x branch). 2. Scope check: audit all files under site/blueprints/users/*.yml for any role configured with users.access: false or users.list: false — only those configurations are exposed. 3. Workaround if patching is delayed: temporarily disable content-locking or set all Panel roles to allow mutual user visibility until the patch is applied. 4. Detection: review Panel access logs for low-privilege role accounts receiving successful 200 responses from endpoints that include lock user payloads (look for repeated requests during active editing sessions from accounts not expected to view users). 5. Post-incident: if a low-privilege account may have been misused, treat all admin email addresses as potentially enumerated and consider phishing-awareness briefings for admin staff.

What systems are affected by CVE-2026-45334?

This vulnerability affects the following AI/ML architecture patterns: CMS-backed AI content portals, AI governance documentation systems, ML model documentation pipelines, Web-based AI management interfaces.

What is the CVSS score for CVE-2026-45334?

No CVSS score has been assigned yet.

What is the AI security impact?

Affected AI Architectures

CMS-backed AI content portalsAI governance documentation systemsML model documentation pipelinesWeb-based AI management interfaces

MITRE ATLAS Techniques

AML.T0012 Valid Accounts

AML.T0049 Exploit Public-Facing Application

AML.T0052 Phishing

AML.T0087 Gather Victim Identity Information

Compliance Controls Affected

EU AI Act: Art. 15

ISO 42001: A.9.3

NIST AI RMF: GOVERN 6.2

OWASP LLM Top 10: LLM02

What are the technical details?

Original Advisory

Kirby is an open-source content management system. In versions prior to 4.9.1 and 5.4.1, the content-locking feature returned lock information without checking the requesting user's access permissions. Kirby's Panel includes a content-locking feature that records which user currently has a model open for editing. This lock prevents conflicting edits by multiple users and displays the locking user's identity in the Panel UI so other users know who to contact. Internally, the locking user's email address and identifier are included in every Panel view payload and in error responses returned when a user attempts to edit a model that is currently locked by another user. This allowed a low-privilege authenticated Panel user, whose role was configured with users.access: false or users.list: false, to learn the email address and identifier of any user who currently had a model open for editing in the Panel, including administrators and other higher-privilege users. Content locks are active for a configurable window (10 minutes by default). The email address can allow admin account enumeration, target phishing, and feed credential-stuffing attacks against the Kirby installation or other sites. The internal user ID can be cross-referenced with other endpoints once the requester has obtained a higher privilege through unrelated means. This issue has been fixed in versions 4.9.1 and 5.4.1.

Exploitation Scenario

An attacker registers or compromises a low-privilege Kirby Panel account — for instance, a guest editor role configured with users.list: false. The attacker monitors for times when administrators are actively editing content, triggering the Panel's content-lock feature. By making ordinary Panel page-view requests during these windows, the attacker receives API responses containing the locking administrator's email address and user ID without any permission check. Repeating this across multiple editing sessions over days yields a complete enumeration of all admin accounts. The harvested emails are then used to launch targeted spearphishing campaigns impersonating Kirby update notifications, or fed into credential-stuffing tools against cloud ML platforms and SaaS services the admins are known to use.

Weaknesses (CWE)

CWE-862 Missing Authorization Primary CWE-862 Missing Authorization Primary CWE-862 Missing Authorization

CWE-862 — Missing Authorization: The product does not perform an authorization check when an actor attempts to access a resource or perform an action.

[Architecture and Design] Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) [REF-229] to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
[Architecture and Design] Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor [REF-7].

Source: MITRE CWE corpus.