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jsbroks COCO Annotator CVE-2026-7681

| EUVDEUVD-2026-26817 MEDIUM
Authorization Bypass Through User-Controlled Key (CWE-639)
2026-05-03 VulDB
5.5
CVSS 4.0 · NVD
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Attack ChainAIDerived

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

  1. Access
    Network reconnaissance
  2. Delivery
    Identify valid DatasetId values
  3. Exploit
    Craft API request with target DatasetId
  4. Execution
    Send unauthenticated HTTP request to Dataset API
  5. Persist
    API processes request without authentication check
  6. Impact
    Attacker reads or modifies dataset contents

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

Remote unauthenticated exploitation against COCO Annotator instances with the Dataset API endpoint (backend/webserver/api/datasets.py) exposed and accessible over the network. The vulnerability requires knowledge of valid dataset identifiers (DatasetIds) belonging to other users or projects, but no special configuration or non-default settings are required-the authorization bypass exists in the default API implementation. The attack is possible against versions 0.11.1 and earlier with no version-specific configuration prerequisites. Exploitation is limited to remote network access scenarios; local exploitation is not applicable. The vulnerability affects the integrity and confidentiality of datasets but does not provide code execution or system-level access.

Impact

CVSS 5.5 (AV:N/AC:L/AT:N/PR:N/UI:N) indicates network-accessible remote exploitation requiring no authentication or user interaction, with moderate impact to data integrity and confidentiality (VI:L/VA:L). The CVSS:4.0 vector with E:P (Exploit Proof-of-Concept) confirms public availability of working exploit code. Risk is elevated by: (1) confirmed public exploit availability reducing barrier to exploitation, (2) no authentication required enabling opportunistic attacks, (3) vendor non-response leaving no patched version available, and (4) the nature of COCO Annotator as a collaborative dataset tool means datasets often contain sensitive training data or labeled information valuable for model development. Real-world risk depends on deployment context: isolated research environments face lower risk than cloud-hosted multi-tenant instances serving external users. The moderate CVSS score reflects limited scope (not full system compromise) but the integrity and confidentiality impacts directly compromise data governance.

Exploit ScenarioDerived

An unauthenticated attacker discovers a COCO Annotator instance accessible over the network and observes valid dataset identifiers through reconnaissance (e.g., error messages, prior public access). The attacker crafts HTTP requests to the Dataset API endpoint with modified DatasetId values corresponding to datasets belonging to other users or projects, without providing authentication credentials. The vulnerable API endpoint accepts these requests and returns or allows modification of dataset metadata and annotations, enabling the attacker to read sensitive training data or corrupt annotations used for model training.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – May 03, 2026

Authorization bypass in jsbroks COCO Annotator up to version 0.11.1 allows remote unauthenticated attackers to modify dataset parameters via manipulation of the DatasetId argument in the Dataset API endpoint backend/webserver/api/datasets.py, enabling unauthorized access to and modification of annotation datasets. Publicly available exploit code exists, and the vendor has not responded to early disclosure notifications.

RemediationAI

No vendor-released patch identified at time of analysis due to vendor non-response to disclosure. Immediate remediation options include: (1) Upgrade from COCO Annotator or discontinue use pending vendor response (recommended if security-critical); (2) Implement API gateway authentication and authorization controls that enforce per-user dataset access restrictions independent of client-supplied DatasetId parameters-validate that the authenticated user has explicit permission to access each dataset before processing the request; (3) Network segmentation: restrict COCO Annotator API access to trusted internal networks only, blocking external and untrusted client access via firewall rules; (4) Add input validation and parameterized access control in backend code (if modifying source) to check user credentials and dataset ownership before returning or modifying dataset objects, ensuring DatasetId alone does not grant access; (5) Implement API request logging and alerting on suspicious DatasetId patterns or cross-user access attempts to detect exploitation attempts. Network restriction is the most effective immediate compensating control but limits usability for distributed teams.

Affected VersionsENISA

COCO Annotator 0.11.0
COCO Annotator 0.11.1

Affected Packages

euvd coco_annotator 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 vulnerability exists in the Dataset API component of COCO Annotator, a collaborative image annotation tool. The affected file backend/webserver/api/datasets.py handles dataset management operations through REST API endpoints. The root cause is classified as CWE-639 (Authorization Bypass Through User-Controlled Key), indicating that the application uses user-supplied input (DatasetId parameter) to determine access control decisions without proper validation of the requester's permissions. The vulnerability suggests the API endpoint trusts client-supplied dataset identifiers to validate ownership or authorization, allowing attackers to reference and manipulate datasets belonging to other users or projects by simply modifying the DatasetId value in their requests.

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Severity by source

NVD PRIMARY 5.5 MEDIUM
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:P

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

Lifecycle Timeline

3
CVSS changed
May 03, 2026 - 06:22 NVD
6.5 (MEDIUM) 5.5 (MEDIUM)
PoC Detected
May 03, 2026 - 06:15 vuln.today
Public exploit code
CVE Published
May 03, 2026 - 05:00 nvd
MEDIUM 5.5

DescriptionCVE.org

A security vulnerability has been detected in jsbroks COCO Annotator up to 0.11.1. Affected by this vulnerability is an unknown functionality of the file backend/webserver/api/datasets.py of the component Dataset API. The manipulation of the argument DatasetId leads to authorization bypass. The attack may be initiated remotely. The exploit has been disclosed publicly and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

Threat Intelligence Overview

EPSS Score
0.0%
Top 89% exploitable
Exploit
POC
Public exploit code exists
Data Quality
7 sources
Confidence: High
EUVD NVD CVE.org EPSS Vulnrichment 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 Yes
EPSS 0.0%
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
None
System Exposure· derived
Open
Automatable
Yes
Human Impact· derived
Medium
Technical Impact
Partial

Priority Score

48
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +28
PoC: +20
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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