CVE-2023-49105 — An issue was discovered in ownCloud owncloud/core before 10

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

01What is this vulnerability?

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.

02Affected products

No structured affected-product list available — see references below for vendor advisories.

03Active exploitation status

Yes — actively exploited. Added to the CISA KEV catalog on 2026-08-27. Ransomware use: Unknown.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Open the Sigma generator with a pre-filled prompt for this CVE to draft a starting detection in your stack of choice:

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07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2023-11-21T22:15:08.613
• Last modified: 2026-08-28T05:16:40.110
• Added to CISA KEV: 2026-08-27

09References

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