CVE-2025-10209 is a medium-severity security vulnerability affecting Papermerge Document Management System (DMS) versions 3.5.0 through 3.5.3. The flaw arises from improper authorization handling within the Authorization Token Handler component. Specifically, the vulnerability allows an attacker to manipulate authorization tokens or related processes remotely without requiring user interaction or elevated privileges beyond low-level privileges. This improper authorization can lead to unauthorized access or actions within the Papermerge DMS environment. The vulnerability has a CVSS 4.0 base score of 5.3, reflecting a network attack vector with low attack complexity and no user interaction required. The impact on confidentiality and availability is limited but present, with integrity also potentially affected to a low degree. The vendor was notified early but has not responded or released patches, and a public exploit has been made available, increasing the risk of exploitation. Papermerge DMS is an open-source document management system used to organize and manage scanned documents and PDFs, often deployed in small to medium enterprises and organizations requiring digital document workflows. The vulnerability could allow attackers to bypass authorization controls, potentially accessing or modifying documents or system functions beyond their privileges, undermining data confidentiality and integrity. Since the exploit is public and the vendor has not issued patches, affected systems remain vulnerable to remote exploitation.

For European organizations using Papermerge DMS, this vulnerability poses a risk of unauthorized access to sensitive documents and data managed within the system. Given that document management systems often contain confidential business, legal, or personal information, exploitation could lead to data breaches, intellectual property theft, or regulatory compliance violations (e.g., GDPR). The ability to remotely exploit the flaw without user interaction or elevated privileges increases the threat level, especially in environments where Papermerge is exposed to untrusted networks or internet-facing. The lack of vendor response and patches means organizations must rely on alternative mitigations. The impact could be more severe in sectors with high confidentiality requirements such as legal firms, healthcare providers, and financial institutions. Additionally, unauthorized modification or deletion of documents could disrupt business operations and workflows, impacting availability and integrity of critical records.

Given the absence of official patches, European organizations should implement the following specific mitigations: 1) Restrict network exposure of Papermerge DMS instances by limiting access to trusted internal networks or VPNs only, blocking all external internet access to the service. 2) Implement strict access controls and monitor authorization token usage for anomalies, including logging and alerting on unusual access patterns. 3) Employ Web Application Firewalls (WAFs) with custom rules to detect and block suspicious requests targeting authorization token manipulation. 4) Conduct regular audits of user permissions within Papermerge to ensure least privilege principles are enforced. 5) Consider deploying intrusion detection systems (IDS) to identify exploitation attempts. 6) If feasible, isolate Papermerge DMS servers in segmented network zones to minimize lateral movement in case of compromise. 7) Stay alert for vendor updates or community patches and plan for timely application once available. 8) As a longer-term measure, evaluate alternative document management solutions with active security support if Papermerge remains unpatched.