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
- 43.19% probability · 99th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Listed 27 August 2026 · due 30 August 2026
- Weakness
- CWE-287
- Affected
- owncloud/owncloud server
- Source
- cve@mitre.org
EPSS 43.2% since 30 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
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, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.