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ApostropheCMS CVE-2026-113655

| EUVDEUVD-2026-105183 MEDIUM
Authorization Bypass Through User-Controlled Key (CWE-639)
2026-10-20 GitHub_M GHSA-2jrp-qc93-h2j8
4.3
CVSS 3.1 · Vendor: GitHub_M
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Attack ChainAIDerived

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

  1. Access
    Authenticate as editor with page edit rights
  2. Exploit
    Invoke same-parent page move on nested page
  3. Impact
    Reorder restricted-parent sibling ranks without create authorization

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V8 - Authorization Object-level authorization, IDOR prevention
Exploitation Conditions

Requires an authenticated user with legitimate editor-level edit rights (PR:L) on a pre-existing ordinary page that is already nested under a restricted parent. The non-default nesting arrangement MUST already exist - the flaw cannot create it. Exploitation is performed specifically through the same-parent page move operation, which fails to enforce create authorization on the parent. Limiting factors: valid editor credentials are mandatory, the restricted nesting must be pre-configured (non-default), and impact is confined to changing sibling ordering/ranks - not arbitrary content modification, data disclosure, or creation of the restricted nesting.

Impact

This is a low-to-moderate priority authorization flaw (CWE-639, IDOR-class) that the CVSS base score of 4.3 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N) accurately reflects. Although the attack vector is network (AV:N) with low complexity (AC:L), exploitation requires legitimate authenticated editor privileges (PR:L) and, critically, a pre-existing non-default page nesting under a restricted parent - so this is not a broadly weaponizable issue. The impact is explicitly bounded: only low integrity (I:L) from reordering sibling page ranks, with no confidentiality (C:N), no availability (A:N), and no ability to create the restricted nesting or modify arbitrary content. No EPSS score, KEV listing, or public POC is present in the provided data; exploitation status is therefore 'no public exploit identified at time of analysis.' All signals are internally consistent - there is no network-vs-local contradiction, and the limited integrity impact matches the narrow description. This is a defense-in-depth authorization fix rather than an urgent, widely-exploitable vulnerability.

Exploit ScenarioDerived

An insider or compromised account holding legitimate editor rights on an ordinary page that already sits under a restricted parent invokes the same-parent page move operation. Because the move path does not re-check create authorization on the parent, the editor reorders the ranks of sibling pages under that restricted parent despite lacking create rights there. No public exploit code is identified; abuse requires existing valid credentials and a pre-existing non-default nesting arrangement.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.3% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 20, 2026

ApostropheCMS before 4.33.0 enables an authenticated editor to alter sibling page ordering under a restricted parent without create authorization on that parent, but only when the nested arrangement already exists. This CWE-639 IDOR-class flaw has a CVSS 3.1 base score of 4.3 (AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N), reflecting low integrity impact, no confidentiality or availability impact, and the editor credential prerequisite. No public exploit identified at time of analysis, and no CISA KEV active exploitation is indicated in the provided data.

RemediationAI

Upgrade ApostropheCMS to 4.33.0 or later; vendor-released patch: 4.33.0, as documented in https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-2jrp-qc93-h2j8 and https://github.com/apostrophecms/apostrophe/releases/tag/apostrophe@4.33.0. If immediate upgrade is not possible, audit the page tree for ordinary pages nested under restricted parents where editors have edit rights but not create rights, then either temporarily remove editor permissions on those specific pages or relocate them to an unrestricted parent using an account with create authorization; this blocks the same-parent move abuse but can disrupt editorial workflows and site hierarchy. Also monitor move and rank-change operations in audit logs and limit editor accounts to pages they are fully authorized to manage until the patch is applied.

Affected VersionsENISA

Apostrophe < 4.33.0

Affected Packages

npm apostrophe fix: 4.33.0

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in npm

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

Technical ContextAI · show details

ApostropheCMS is an open-source Node.js content management system with a page tree and sibling ordering; the affected CPE string cpe:2.3:a:apostrophecms:apostrophe:*:*:*:*:*:*:*:* is consistent with the vendor's prior-to-4.33.0 version range. The root cause falls under CWE-639, Authorization Bypass Through User-Controlled Key, often described as an IDOR, because the same-parent page move operation relies on user-controlled page references or ranks and fails to enforce create authorization on the parent. Exploitation requires a legitimate editor account with edit rights on a pre-existing ordinary page already nested under a restricted parent, and the non-default nesting must already exist; the flaw cannot create it. Impact is limited to changing sibling rank ordering rather than arbitrary content modification, data disclosure, or creation of the restricted nesting.

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Severity by source

Vendor (GitHub_M) PRIMARY 4.3 MEDIUM
AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
vuln.today AI 4.3 MEDIUM

Network-reachable editor action with no UI, but requires authenticated editor rights (PR:L); only low integrity from sibling reordering, no confidentiality or availability impact.

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

Primary rating from Vendor (GitHub_M).

CVSS VectorVendor: GitHub_M

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

Lifecycle Timeline

1
Patch available
Oct 20, 2026 - 18:17 EUVD

DescriptionCVE.org

ApostropheCMS is an open-source Node.js content management system. Prior to 4.33.0, an authenticated editor with legitimate edit rights on a pre-existing ordinary page nested under a restricted parent can use the same-parent page move operation to change sibling ranks without create authorization on that parent. The non-default nesting must already exist, and the bypass is limited to sibling ordering rather than arbitrary content modification, confidentiality loss, or creation of the restricted nesting. This issue is fixed in version 4.33.0.

Threat Intelligence Overview

EPSS Score
0.3%
Top 76% exploitable
Prevalence
Low
niche open-source Node.js CMS, limited enterprise deployment footprint
Threat Intel
1
1 source
Social Media
1
Sightings
Data Quality
6 sources
Confidence: High
EUVD NVD CVE.org EPSS Vulnrichment GHSA CIRCL GitHub VulDB

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 MEDIUM
CISA KEV No
Public POC No
EPSS 0.3%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
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· derived
Scheduled
Exploitation
Poc
System Exposure· derived
Open
Automatable
No
Human Impact· derived
Medium
Technical Impact
Partial

Priority Score

22
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +22
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

CVE-2026-63669 MEDIUM POC
6.5 Aug 17

Integrity bypass in ApostropheCMS page management allows authenticated low-privileged editors to move pages into restric

CVE-2026-63670 MEDIUM POC
6.1 Aug 17

Stored cross-site scripting in ApostropheCMS prior to 2.17.6 enables execution of arbitrary JavaScript in victim browser

CVE-2014-125128 MEDIUM POC
6.1 Sep 08

'sanitize-html' prior to version 1.0.3 is vulnerable to Cross-site Scripting (XSS). Rated medium severity (CVSS 6.1), th

CVE-2019-25225 MEDIUM POC
6.1 Sep 08

`sanitize-html` prior to version 2.0.0-beta is vulnerable to Cross-site Scripting (XSS). Rated medium severity (CVSS 6.1

CVE-2021-25979 CRITICAL
9.8 Nov 08

Apostrophe CMS versions prior to 3.3.1 did not invalidate existing login sessions when disabling a user account or chang

CVE-2026-84371 MEDIUM POC
5.4 Sep 01

Stored XSS in sanitize-html versions 1.9.0 through 2.17.6 allows authenticated low-privileged users to inject executable

CVE-2024-21501 MEDIUM POC
5.3 Feb 24

Versions of the package sanitize-html before 2.12.1 are vulnerable to Information Exposure when used on the backend and

CVE-2021-26540 MEDIUM POC
5.3 Feb 08

Apostrophe Technologies sanitize-html before 2.3.2 does not properly validate the hostnames set by the "allowedIframeHos

CVE-2021-26539 MEDIUM POC
5.3 Feb 08

Apostrophe Technologies sanitize-html before 2.3.1 does not properly handle internationalized domain name (IDN) which co

CVE-2026-53609 CRITICAL
9.1 Jun 12

Prototype pollution in ApostropheCMS versions up to and including 4.30.0 allows an authenticated editor to poison Object

CVE-2026-53608 HIGH
8.7 Jun 12

Stored cross-site scripting in the @apostrophecms/seo plugin (versions ≤1.4.2) allows any user holding the default edito

CVE-2026-35569 HIGH
8.7 Apr 15

Stored cross-site scripting in ApostropheCMS SEO fields permits an authenticated attacker to inject arbitrary JavaScript

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