---
title: "CVE-2023-49105: ownCloud Improper Authentication Vulnerability"
url: https://erroneo.us/security/cve/CVE-2023-49105/
description: "CVE-2023-49105 (ownCloud ownCloud): Exploited in the wild (CISA KEV). An issue was discovered in ownCloud owncloud/core before 10.13.1. An attacker can…"
type: vulnerability-record
section: "Security Digest"
date_published: 2023-11-21
date_modified: 2026-10-21
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2023-49105"
kev: true
cvss: 9.8
epss: 0.4319
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2023-49105: ownCloud Improper Authentication Vulnerability

**Signal:** Exploited: patch now if you run it. CISA has confirmed exploitation in the wild. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Yes, if you run ownCloud ownCloud. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2026-08-27, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2026-08-30 ; treat that as the outer limit, not the target.
- EPSS 43.2% , percentile 99: FIRST’s model estimates a 43.2% chance of exploitation activity in the next 30 days, higher than 99% of all scored CVEs (very high). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Editorial verdict: Check exposure. ownCloud CVE-2023-49105: 2023 WebDAV Bypass Now in KEV — Up-to-date ownCloud servers are fine; any ownCloud core 10.6.0 to 10.13.0 still online should be upgraded today and treated as breached, because attackers are using this bug to empty file shares.

## What it is

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.

## Affected products (CVE record)

- n/a n/a: see advisory

## Severity

- mitre CVSS 3.1: 9.8 `CVSS:3.1/AC:L/AV:N/A:H/C:H/I:H/PR:N/S:U/UI:N`

## Exploitation

- CISA KEV: added 2026-08-27; federal due date 2026-08-30. Known ransomware use: Unknown.
- CISA 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.
- CISA SSVC assessment: exploitation active , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 43.19% probability of exploitation activity in the next 30 days; percentile 99.

## Sources

- [Listed in CISA KEV notes (owncloud.org)](https://owncloud.org/security)
- [Listed in CISA KEV notes (owncloud.com)](https://owncloud.com/security-advisories/webdav-api-authentication-bypass-using-pre-signed-urls/)
- [CVE.org record CVE-2023-49105](https://www.cve.org/CVERecord?id=CVE-2023-49105)
- [NVD entry CVE-2023-49105](https://nvd.nist.gov/vuln/detail/CVE-2023-49105)
- [CISA Known Exploited Vulnerabilities catalog entry](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-49105)
- [Listed in CISA KEV notes (cisa.gov)](https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk)
- [Listed in CISA KEV notes (cisa.gov)](https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk)
- [hunt.io](https://hunt.io/blog/chinese-speaking-operator-philippine-nuclear-naval-contractor)

---
Source page: https://erroneo.us/security/cve/CVE-2023-49105/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt