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CamaleonCMS CVE-2026-73329

| EUVDEUVD-2026-57428 CRITICAL
Cross-site Scripting (XSS) (CWE-79)
2026-08-12 VulnCheck GHSA-mf3v-84v4-vjjc
9.2
CVSS 4.0 · Vendor: VulnCheck
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Authenticate as low-privileged user
  2. Delivery
    Submit draft with malicious HTML title
  3. Exploit
    Payload stored unescaped in database
  4. Execution
    Admin opens drafts listing
  5. Persist
    Script executes in admin session
  6. Impact
    Steal cookies / forge admin requests

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V1 - Encoding and Sanitization Output encoding, context-aware escaping
MITRE ATT&CK

2 techniques across 2 tactics: Initial Access, Execution

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Exploitation requires an authenticated account with at least low privileges (PR:L) able to reach the drafts creation endpoint and submit a post title, plus the specific product feature of unsanitized draft-title storage and the admin drafts listing view being the rendering sink. It is limited by user interaction (UI:A): an administrator must load the admin drafts listing page for the stored payload to execute, so it is not fully autonomous. There is no unauthenticated path - a low-privileged foothold in the CamaleonCMS admin/content area is a hard prerequisite, and exploitation depends on at least one privileged user viewing the drafts screen.

Impact

The CVSS 4.0 score of 9.2 (Critical) reflects network attack vector (AV:N), low complexity (AC:L), only low privileges required (PR:L), and a scope/subsequent-system impact (SC:H/SI:H) representing the pivot into the admin's context - but it is tempered by UI:A, meaning an administrator must actually view the drafts page for the payload to fire. There is no EPSS score provided and no CISA KEV listing, so there is no evidence of active exploitation; the risk is real but conditional on both a low-privileged foothold and admin interaction. A detailed public write-up exists (enrik-m blog and VulnCheck advisory), which lowers the bar to reproduce even though formal exploit code is not confirmed. Net assessment: a genuine, high-value privilege-escalation vector in any multi-user CamaleonCMS deployment, not merely an inflated high-CVSS score, though real-world exploitation is targeted (insider/low-priv-to-admin) rather than mass, internet-scale automatable.

Exploit ScenarioDerived

A low-privileged authenticated user (e.g., a contributor account) submits a draft whose title contains a script payload such as an image tag with an onerror handler through the drafts creation endpoint. The payload is stored unescaped and executes automatically the next time an administrator opens the admin drafts listing, exfiltrating the admin's session cookie or issuing forged administrative actions. A public technical write-up describing the exact endpoint and sink exists, lowering the effort to reproduce, though no packaged exploit is confirmed.

Act Now Prioritize within 24-48h. Why: CRITICAL severity.
Patch available 0.2% exploitation probability (EPSS)

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AnalysisAIv1 – Aug 12, 2026

Stored cross-site scripting in CamaleonCMS (owen2345/camaleon-cms) lets an authenticated low-privileged user persist a malicious HTML/JavaScript payload as a draft post title, which executes in an administrator's browser when the admin views the drafts listing. Because the payload runs in the admin's authenticated session, it enables session/cookie theft and forged administrative requests, effectively escalating a low-privileged account to admin-level control. Reported by VulnCheck with a public technical write-up; no public exploit identified at time of analysis and not listed in CISA KEV.

RemediationAI

Patch available per vendor advisory - upgrade CamaleonCMS to the fixed release from the vendor repository at https://github.com/owen2345/camaleon-cms; the input data confirms a patch is available but does not specify an exact fixed version, so verify the patched tag/release against the vendor changelog and the VulnCheck advisory (https://www.vulncheck.com/advisories/camaleoncms-stored-xss-via-draft-post-title-creation-endpoint) before deploying. If immediate patching is not possible, apply compensating controls: enforce server-side HTML sanitization/escaping of the draft post title on both input and output (the drafts listing render path is the sink), restrict draft creation to trusted roles by tightening role permissions so low-privileged accounts cannot submit drafts, and deploy a Content-Security-Policy that disallows inline script execution in the admin panel - note that a strict CSP may break legitimate inline admin scripts and require testing. As an interim monitoring control, audit existing draft titles for embedded HTML/script markup before an admin opens the drafts list.

Affected VersionsENISA

CamaleonCMS 0 ≤2.9.1

Affected Packages

euvd camaleoncms no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

CamaleonCMS is a Ruby on Rails-based, database-backed content management system. The flaw is a classic CWE-79 (Improper Neutralization of Input During Web Page Generation) stored/persistent XSS: input supplied to the post title parameter at the drafts creation endpoint is written to the database without HTML escaping and later emitted as raw HTML in the admin drafts listing view, so the browser parses attacker markup as executable script. The affected component is identified by CPE cpe:2.3:a:owen2345:camaleoncms:*:*:*:*:*:*:*:*, covering all versions prior to the vendor fix. The root cause is missing output encoding/sanitization on a server-rendered admin template combined with insufficient input validation on a content field.

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Severity by source

Vendor (VulnCheck) PRIMARY 9.2 CRITICAL
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N
vuln.today AI 8.7 HIGH

Authenticated low-priv user injects the payload (PR:L) but an admin must view the drafts page (UI:R); execution in the admin context crosses a trust boundary (S:C) yielding high confidentiality/integrity impact and no availability impact.

3.1 AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
4.0 AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N

Primary rating from Vendor (VulnCheck).

CVSS VectorVendor: VulnCheck

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
Low
User Interaction
Active
Vulnerable system: Confidentiality
High
Vulnerable system: Integrity
High
Vulnerable system: Availability
None
Subsequent system: Confidentiality
High
Subsequent system: Integrity
High
Subsequent system: Availability
None

DescriptionCVE.org

CamaleonCMS contains a stored cross-site scripting vulnerability that allows authenticated low-privileged users to execute arbitrary JavaScript in an administrator's browser by injecting unsanitized HTML payloads into the post title parameter during draft creation. Attackers can submit a malicious HTML payload as a draft title through the drafts creation endpoint, which is persisted to the database without escaping and later rendered as raw HTML in the admin drafts listing, enabling administrator session compromise, cookie theft, and forged authenticated requests.

Executive ViewAI

Why It Matters

CamaleonCMS installations face complete administrative account takeover via stored cross-site scripting in draft posts. Any low-privilege user (contributor, editor) can inject malicious code that executes in administrators' browsers, enabling session theft and full platform compromise. Organizations with CamaleonCMS and multiple user accounts face immediate risk of data breach, website defacement, and loss of operational control.

Business Impact: Severe
Compensating Controls

Apply vendor patch.

Threat Intelligence Overview

EPSS Score
0.2%
Top 86% exploitable
Prevalence
Low
niche open-source Rails CMS with limited enterprise deployment footprint
Data Quality
6 sources
Confidence: High

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity CRITICAL
CISA KEV No
Public POC No
EPSS 0.2%
Patch available Yes
Active threat No
Deciding rule
CRITICAL severity
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
No
Human Impact
Very High
Technical Impact
Partial

Priority Score

46
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +46
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Cross-Site Scripting occurs when an application accepts untrusted data and sends it to a web browser without proper validation or encoding.

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