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PatchSiren cyber security CVE debrief

CVE-2026-38587 ONLYOFFICE CVE debrief

An Insecure Direct Object Reference (IDOR) vulnerability in ONLYOFFICE DocSpace before version 3.2.1 allows authenticated users with low-level permissions (User or Guest) to access sensitive administrative information through multiple REST API endpoints. The flaw enables unauthorized retrieval of the Owner's unique identifier and profile information, which should be restricted to administrators. The vulnerability was published on 2026-05-26 and carries a CVSS 3.1 score of 4.3 (Medium severity). The issue has been addressed in DocSpace version 3.2.1, as documented in the project's security changelog.

Vendor
ONLYOFFICE
Product
DocSpace
CVSS
MEDIUM 4.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-26
Original CVE updated
2026-05-26
Advisory published
2026-05-26
Advisory updated
2026-05-26

Who should care

Organizations running ONLYOFFICE DocSpace instances with multi-user environments where Guest or standard User accounts are provisioned. System administrators responsible for access control policies and security compliance in document collaboration platforms. Security teams monitoring for IDOR vulnerabilities in REST API implementations.

Technical summary

The vulnerability exists in multiple REST API endpoints within ONLYOFFICE DocSpace versions prior to 3.2.1. The IDOR flaw allows authenticated users with minimal permissions (User or Guest roles) to bypass authorization controls and directly reference objects belonging to the Owner account. This results in unauthorized disclosure of sensitive administrative information including the Owner's unique identifier and profile details. The attack requires network access and valid low-privilege credentials, with no user interaction needed. The confidentiality impact is rated low per CVSS, as the exposure is limited to information disclosure without integrity or availability effects.

Defensive priority

medium

Recommended defensive actions

  • Upgrade ONLYOFFICE DocSpace to version 3.2.1 or later to remediate the IDOR vulnerability
  • Review REST API endpoint access controls to ensure proper authorization checks are enforced for all sensitive data retrieval operations
  • Audit user access logs for potential unauthorized access to owner profile information prior to patching
  • Implement defense-in-depth by validating user permissions at both the API gateway and application layers for administrative data endpoints

Evidence notes

The vulnerability is documented in the ONLYOFFICE DocSpace CHANGELOG security section, which confirms the IDOR issue was resolved in version 3.2.1. The NVD record indicates deferred status with CVSS vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N, reflecting network attack vector, low attack complexity, low privileges required, and low confidentiality impact. CWE-639 (Authorization Bypass Through User-Controlled Key) is identified as the weakness type.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-38587 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-38587

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-38587 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-38587

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.