What’s Vulnerable › Vulnerabilities

CVE-2023-49105: ownCloud Improper Authentication Vulnerability

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: yes — in CISA KEV since 2026-08-27
• EPSS: 43.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2023-11-21 · updated 2026-08-28
• Weakness: CWE-287

Description

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: from 10.6.0 before 10.13.1 — fixed in 10.13.1

How to fix

Upgrade to a fixed version: ownCloud 10.13.1. Check the vendor advisory for mitigations.

References

• https://owncloud.com/security-advisories/webdav-api-authentication-bypass-using-pre-signed-urls/
• https://owncloud.org/security
• https://owncloud.com/security-advisories/webdav-api-authentication-bypass-using-pre-signed-urls/
• https://owncloud.org/security
• https://hunt.io/blog/chinese-speaking-operator-philippine-nuclear-naval-contractor
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-49105

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