CVE-2023-49105: ownCloud Improper Authentication Vulnerability

Critical severity, CVSS 9.8. Actively exploited: in CISA KEV since 2026-08-27. EPSS: 42.9% chance of exploitation in the next 30 days.

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.

Affected products

• ownCloud ownCloud Server: from 10.6.0, before 10.13.1 (fixed in 10.13.1)

Published 2023-11-21. Last modified 2026-08-28.