CVE-2023-49105: ownCloud Improper Authentication Vulnerability

CVE-2023-49105: ownCloud Improper Authentication Vulnerability
Vendor/project: ownCloud
Product: ownCloud
Date added to KEV: 2026-08-27
Due date: 2026-08-30
Known ransomware use: Unknown
CWEs: CWE-287
ownCloud contains an improper authentication vulnerability that allows an attacker to access, modify, or delete any file without authentication if the username of a victim is known, and the victim has no signing-key configured.

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.

Notes:
https://owncloud.org/security ; https://owncloud.com/security-advisories/webdav-api-authentication-bypass-using-pre-signed-urls/ ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2023-49105
CISA KEV catalog entry for CVE-2023-49105
Original source: https://owncloud.org/security