CVE-2023-49105
ownCloud Improper Authentication Vulnerability
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 30 August 2026). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
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.
- CVSS 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 43.20% probability · 99th percentile
- CISA KEV
- Listed 27 August 2026 · due 30 August 2026
- Weakness
- CWE-287
- Affected
- owncloud/owncloud server
- Source
- cve@mitre.org
CISA notes
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. 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
References
- https://owncloud.com/security-advisories/webdav-api-authentication-bypass-using-pre-signed-urls/Vendor Advisory
- https://owncloud.org/securityProduct
- https://owncloud.com/security-advisories/webdav-api-authentication-bypass-using-pre-signed-urls/Vendor Advisory
- https://owncloud.org/securityProduct
- https://hunt.io/blog/chinese-speaking-operator-philippine-nuclear-naval-contractorThird Party Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-49105US Government Resource
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.