Actively exploited in the wild
ownCloud Improper Authentication Vulnerability
ownCloud - ownCloud · Listed in the CISA KEV since 2026-08-27. This indicates confirmed attacks in production environments.
Required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
CVE-2023-49105
CriticalCVSS 9.8KEVExploitation Probability (EPSS)
Very high risk99th percentile - higher than 99% of all known CVEs
Summary
In ownCloud core before version 10.13.1, an attacker can access, modify, or delete any file without authentication if the victim's username is known and the victim has no signing-key configured. This occurs because pre-signed URLs can be accepted even when no signing-key is configured for the file owner. The earliest affected version is 10.6.0.
Risk Assessment
The risk includes unauthorized access, modification, or deletion of data, potentially leading to confidentiality and integrity breaches in the organization.
Recommendation
Immediately upgrade ownCloud core to version 10.13.1 or later and ensure signing keys are configured for all users.
Other vulnerabilities in ownCloud
See all- CVE-2025-53829High
In ownCloud 10 prior to version 10.15.3, a path traversal vulnerability allows an attacker with administrative privileges to execute arbitrary code. The issue is fixed in version 10.15.3.
- CVE-2025-53828High
In SharePoint for ownCloud prior to version 0.4.1 (corresponding to ownCloud 10 before 10.15.3), an SSRF vulnerability allows an attacker with administrative privileges to execute arbitrary code on the system.
Original NVD description (English source)
An issue was discovered in ownCloud owncloud/core before 10.13.1. An attacker can access, modify, or delete any file without authentication if the username of a victim is known, and the victim has no signing-key configured. This occurs because pre-signed URLs can be accepted even when no signing-key is configured for the owner of the files. The earliest affected version is 10.6.0.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS