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MrDoc CVE-2026-111645

| EUVDEUVD-2026-103067 MEDIUM
Authorization Bypass Through User-Controlled Key (CWE-639)
2026-10-16 VulnCheck GHSA-x63c-25rw-gwj4
5.3
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
    Register or obtain low-privilege MrDoc account
  2. Delivery
    Enumerate other users' document/project IDs
  3. Exploit
    Send PUT to ImportLocalDoc with foreign sort_data IDs
  4. Execution
    Reparent documents and publish private drafts
  5. Impact
    Cross-user data tampering and disclosure

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 a valid authenticated MrDoc account (PR:L) with access to the ImportLocalDoc API; the attacker must know or enumerate another user's document IDs (sort_data) or project top_doc IDs, which the API accepts without verifying object ownership. Exploitation works over the network against standard multi-user MrDoc installations with no victim interaction (UI:N) and no non-default configuration, but is limited to the application's authorization boundary: it affects only document/project data the attacker can reference, cannot escalate to the host, and depends on the deployment being multi-tenant (single-user instances have no cross-user victim).

Impact

This is a moderate-severity object-level authorization flaw (CWE-639 / IDOR) whose signals are internally consistent rather than alarming. The provided CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N) scores 5.3 and correctly reflects a network-reachable, low-complexity bug that nonetheless requires PR:L - i.e. an already-authenticated application account. There is no CISA KEV listing and the input provides no explicit POC flag, so exploitation status is 'no public exploit identified at time of analysis'; however, a detailed third-party technical writeup (hackmd) and a VulnCheck advisory with a direct source-code line reference exist, which materially lowers the research/reverse-engineering barrier even without packaged exploit code. No EPSS score was supplied, so widespread-automated-exploitation probability cannot be quantified from the data. Impact is bounded: C:L/I:L with A:N means an attacker can read/modify or reparent other users' documents and publish private drafts, but cannot destroy availability or gain system-level control. Net assessment: a legitimate data-integrity/confidentiality issue for multi-tenant MrDoc deployments, but not a drop-everything priority - the authentication prerequisite and limited, scope-unchanged impact keep real-world risk in the medium band. Key missing data to verify: EPSS, independent confirmation of a patched version, and whether any public PoC is embedded in the referenced writeup.

Exploit ScenarioDerived

An attacker who holds any ordinary authenticated MrDoc account sends a crafted PUT request to the ImportLocalDoc API supplying sort_data document IDs belonging to another user, causing that victim's private drafts to be published and their documents reparented under attacker-controlled structure; a POST with arbitrary top_doc IDs can inject documents into another user's project. Because AC:L and UI:N, no victim interaction or special timing is needed - only a valid session. No packaged public exploit is confirmed, but a step-by-step technical writeup and the vulnerable source lines are publicly referenced.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.2% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 16, 2026

Missing object-level authorization in MrDoc through 1.1.1 lets any authenticated user publish other users' private drafts, reparent their documents, and inject documents into projects they do not own by supplying arbitrary document or project identifiers to the ImportLocalDoc API. The flaw is a classic insecure direct object reference (CWE-639) assessed at 5.3 (CVSS:4.0 AV:N/AC:L/PR:L/UI:N, low confidentiality and integrity impact) and is confined to the application's own authorization boundary: it cannot reach the host, and it requires a multi-user deployment in which a victim's document or project actually exists. No public exploit code was identified at time of analysis and the CVE is not listed in CISA KEV, though a public technical writeup documents the endpoint's behavior.

RemediationAI

No vendor-released patch was identified in the available intelligence at time of analysis, so the primary action is to track the upstream MrDoc project (zmister2016/MrDoc) and the referenced advisories for a fixed release before upgrading. Until a patched version is published, apply compensating controls at the application boundary: disable or block access to the ImportLocalDoc endpoint in app_doc/views_import.py (for example via a reverse-proxy rule or by removing the route) for all but a trusted administrative role, accepting that the local-document import feature will be unavailable to normal users; alternatively, restrict MrDoc deployments to single-user or fully trusted user sets, since the vulnerability is only exploitable cross-user and single-user instances have no victim object to modify. Because exploitation depends on the attacker knowing or enumerating document IDs (sort_data) or project top_doc IDs, reducing identifier discoverability (avoiding sequential or predictable IDs, restricting project listing endpoints) raises cost but does not remove the flaw. If the ImportLocalDoc handler can be locally modified, add per-object ownership checks that confirm the requester owns or is authorized on the referenced sort_data document IDs and top_doc IDs before allowing publish, reparent, or inject operations; a side effect of this code change is the need to re-apply it on every upstream update. Review existing logs for unusual PUT/POST traffic to the ImportLocalDoc route and audit documents/projects for unauthorized publish or reparenting events to detect prior abuse.

Affected VersionsENISA

MrDoc 0 ≤1.1.1

Affected Packages

euvd mrdoc 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

The root cause is CWE-639, authorization bypass through a user-controlled key, in MrDoc's ImportLocalDoc view (app_doc/views_import.py, lines 165-182 of v1.1.1). The endpoint accepts client-supplied identifiers for the objects it operates on: a PUT request with arbitrary sort_data document IDs is used to publish private drafts and change document parentage, while a POST with arbitrary top_doc IDs injects documents into projects. Because the handler acts on those IDs without verifying that the requesting account owns or has permission over the referenced document or project, any user holding a valid MrDoc account (CVSS vector PR:L) can manipulate objects belonging to other users. The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N) confirms network reachability, no authentication bypass beyond the low-privilege account prerequisite, no user interaction, and low confidentiality/integrity impact with no availability impact; the independent assessment reaches the same conclusion under CVSS 3.1 (AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N). CPE data identifies the affected package as cpe:2.3:a:zmister2016:mrdoc:*:*:*:*:*:*:*:*, i.e. MrDoc versions up to and including 1.1.1.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (VulnCheck) PRIMARY 5.3 MEDIUM
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
vuln.today AI 5.4 MEDIUM

Network API reachable with low complexity, but a valid authenticated account is required (PR:L); cross-user read and tampering give C:L/I:L, with no availability impact and no scope change.

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

Primary rating from Vendor (VulnCheck).

CVSS VectorVendor: VulnCheck

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

DescriptionCVE.org

MrDoc through 1.1.1 contains a missing object-level authorization vulnerability in the ImportLocalDoc API that allows authenticated users to modify other users' documents and projects. Attackers can send PUT requests with arbitrary sort_data document ids to publish private drafts and reparent documents, or POST with arbitrary top_doc ids to inject documents.

Threat Intelligence Overview

EPSS Score
0.2%
Top 89% exploitable
Prevalence
Low
niche open-source wiki/documentation tool, limited enterprise footprint
Data Quality
5 sources
Confidence: Medium

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 0.2%
Patch available No
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· derived
None
System Exposure· derived
Open
Automatable· derived
No
Human Impact· derived
Medium

Priority Score

26
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +26
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.

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