CVE-2023-49105

KEVownCloud Improper Authentication Vulnerability

Description

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.

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 vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

PublishedNov 21, 2023

Last modifiedAug 28, 2026

Added to KEVAug 27, 2026

Remediation dueAug 30, 2026

References

owncloud.com/security-advisories/webdav-api-authentication-bypass-using-pre-signed-urls/Vendor Advisory
owncloud.org/securityProduct
hunt.io/blog/chinese-speaking-operator-philippine-nuclear-naval-contractorThird Party Advisory
cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-49105US Government Resource

0 recent articles mention this CVE

Risk assessment · Critical

Actively exploited. Patch immediately.

Exploitation: Confirmed in the wild (CISA KEV)
Federal remediation deadline: Overdue by 58 days
CVSS: 9.8 CRITICAL
EPSS (30-day exploit probability): 43.2% · top 1% of all CVEs
Weakness: CWE-287
Attack vector: Network, remotely reachable
Preconditions: No privileges and no user interaction

Recommended actions

1.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.
2.Treat as emergency change: patch or isolate internet-facing instances first.
3.Review exposure: confirm which instances are reachable from the internet and restrict access until patched.
4.Hunt for compromise: review logs for the disclosure window, not just from the patch date.

Assessment is derived automatically from the live signals above; verify against your own asset inventory.