CVE-2023-49105
ownCloud Improper Authentication Vulnerability
ownCloud ownCloud
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.
Exploitation status
CISA Known Exploited Vulnerabilities
Listed by CISA on 27 August 2026. US federal agencies were required to remediate it by 30 August 2026.
EPSS — exploitation probability
FIRST puts the probability of exploitation activity in the next 30 days at 43.2%, which is higher than 98.6% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Frequently asked questions
Is CVE-2023-49105 being exploited by ransomware groups?
No ransomware group in this database is currently recorded as exploiting CVE-2023-49105.
What does CVE-2023-49105 affect?
CVE-2023-49105 affects ownCloud ownCloud. 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.
How severe is CVE-2023-49105?
CVE-2023-49105 is rated CRITICAL with a CVSS base score of 9.8. EPSS puts the probability of exploitation in the next 30 days at 43.2%, higher than 98.6% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 30 August 2026.
How should organisations respond to CVE-2023-49105?
Apply the vendor patch for ownCloud ownCloud as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.